AttributeError: 'str' object has no attribute '_meta'

[sagar ninave]

System check identified no issues (0 silenced).
May 22, 2019 - 22:03:40
Django version 2.2.1, using settings 'freewareinfoapi.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.
india
china
Internal Server Error: /countryapi/getcountries/
Traceback (most recent call last):
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
    response = get_response(request)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\views\generic\base.py", line 71, in view
    return self.dispatch(request, *args, **kwargs)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\views.py", line 495, in dispatch
    response = self.handle_exception(exc)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\views.py", line 455, in handle_exception
    self.raise_uncaught_exception(exc)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\views.py", line 492, in dispatch
    response = handler(request, *args, **kwargs)
  File "D:\DjangoRestApi\freewareinfoapi\country\views.py", line 18, in get
    return Response({'status': True, 'country': CountrySerializer(countries, many = True).data})
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 768, in data
    ret = super(ListSerializer, self).data
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 262, in data
    self._data = self.to_representation(self.instance)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 686, in to_representation
    self.child.to_representation(item) for item in iterable
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 686, in <listcomp>
    self.child.to_representation(item) for item in iterable
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 513, in to_representation
    fields = self._readable_fields
  File "D:\DjangoRestApi\venv\lib\site-packages\django\utils\functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 376, in _readable_fields
    field for field in self.fields.values()
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 363, in fields
    for key, value in self.get_fields().items():
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 1024, in get_fields
    info = model_meta.get_field_info(model)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\utils\model_meta.py", line 35, in get_field_info
    opts = model._meta.concrete_model._meta
AttributeError: 'str' object has no attribute '_meta'
[22/May/2019 22:03:59] "GET /countryapi/getcountries/ HTTP/1.1" 500 127237
Not Found: /favicon.ico
[22/May/2019 22:03:59] "GET /favicon.ico HTTP/1.1" 404 2092
Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 138, in run
    self.finish_response()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 180, in finish_response
    self.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 274, in write
    self.send_headers()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 332, in send_headers
    self.send_preamble()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 255, in send_preamble
    ('Date: %s\r\n' % format_date_time(time.time())).encode('iso-8859-1')
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 453, in _write
    result = self.stdout.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 796, in write
    self._sock.sendall(b)
ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine
[22/May/2019 22:03:59] "GET /favicon.ico HTTP/1.1" 500 59
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 49753)
Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 138, in run
    self.finish_response()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 180, in finish_response
    self.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 274, in write
    self.send_headers()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 332, in send_headers
    self.send_preamble()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 255, in send_preamble
    ('Date: %s\r\n' % format_date_time(time.time())).encode('iso-8859-1')
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 453, in _write
    result = self.stdout.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 796, in write
    self._sock.sendall(b)
ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 141, in run
    self.handle_error()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 116, in handle_error
    super().handle_error()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 368, in handle_error
    self.finish_response()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 180, in finish_response
    self.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 274, in write
    self.send_headers()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 331, in send_headers
    if not self.origin_server or self.client_is_modern():
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 344, in client_is_modern
    return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
TypeError: 'NoneType' object is not subscriptable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 647, in process_request_thread
    self.finish_request(request, client_address)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 357, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 717, in __init__
    self.handle()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 171, in handle
    self.handle_one_request()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 194, in handle_one_request
    handler.run(self.server.get_app())
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 144, in run
    self.close()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 111, in close
    super().close()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\simple_server.py", line 35, in close
    self.status.split(' ',1)[0], self.bytes_sent
AttributeError: 'NoneType' object has no attribute 'split'
----------------------------------------
D:\DjangoRestApi\freewareinfoapi\country\views.py changed, reloading.
Watching for file changes with StatReloader
Performing system checks...

System check identified no issues (0 silenced).
May 22, 2019 - 22:04:42
Django version 2.2.1, using settings 'freewareinfoapi.settings'
Starting development server at http://127.0.0.1:8000/
Quit the server with CTRL-BREAK.
Internal Server Error: /countryapi/getcountries/
Traceback (most recent call last):
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
    response = get_response(request)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\handlers\base.py", line 115, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\handlers\base.py", line 113, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\views\decorators\csrf.py", line 54, in wrapped_view
    return view_func(*args, **kwargs)
  File "D:\DjangoRestApi\venv\lib\site-packages\django\views\generic\base.py", line 71, in view
    return self.dispatch(request, *args, **kwargs)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\views.py", line 495, in dispatch
    response = self.handle_exception(exc)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\views.py", line 455, in handle_exception
    self.raise_uncaught_exception(exc)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\views.py", line 492, in dispatch
    response = handler(request, *args, **kwargs)
  File "D:\DjangoRestApi\freewareinfoapi\country\views.py", line 18, in get
    return Response({'status': True, 'country': CountrySerializer(countries, many = True).data})
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 768, in data
    ret = super(ListSerializer, self).data
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 262, in data
    self._data = self.to_representation(self.instance)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 686, in to_representation
    self.child.to_representation(item) for item in iterable
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 686, in <listcomp>
    self.child.to_representation(item) for item in iterable
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 513, in to_representation
    fields = self._readable_fields
  File "D:\DjangoRestApi\venv\lib\site-packages\django\utils\functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 376, in _readable_fields
    field for field in self.fields.values()
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 363, in fields
    for key, value in self.get_fields().items():
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\serializers.py", line 1024, in get_fields
    info = model_meta.get_field_info(model)
  File "D:\DjangoRestApi\venv\lib\site-packages\rest_framework\utils\model_meta.py", line 35, in get_field_info
    opts = model._meta.concrete_model._meta
AttributeError: 'str' object has no attribute '_meta'
[22/May/2019 22:04:44] "GET /countryapi/getcountries/ HTTP/1.1" 500 127070
Not Found: /favicon.ico
[22/May/2019 22:04:45] "GET /favicon.ico HTTP/1.1" 404 2092
Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 138, in run
    self.finish_response()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 180, in finish_response
    self.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 274, in write
    self.send_headers()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 332, in send_headers
    self.send_preamble()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 255, in send_preamble
    ('Date: %s\r\n' % format_date_time(time.time())).encode('iso-8859-1')
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 453, in _write
    result = self.stdout.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 796, in write
    self._sock.sendall(b)
ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine
[22/May/2019 22:04:45] "GET /favicon.ico HTTP/1.1" 500 59
----------------------------------------
Exception happened during processing of request from ('127.0.0.1', 49754)
Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 138, in run
    self.finish_response()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 180, in finish_response
    self.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 274, in write
    self.send_headers()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 332, in send_headers
    self.send_preamble()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 255, in send_preamble
    ('Date: %s\r\n' % format_date_time(time.time())).encode('iso-8859-1')
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 453, in _write
    result = self.stdout.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 796, in write
    self._sock.sendall(b)
ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 141, in run
    self.handle_error()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 116, in handle_error
    super().handle_error()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 368, in handle_error
    self.finish_response()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 180, in finish_response
    self.write(data)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 274, in write
    self.send_headers()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 331, in send_headers
    if not self.origin_server or self.client_is_modern():
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 344, in client_is_modern
    return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
TypeError: 'NoneType' object is not subscriptable

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 647, in process_request_thread
    self.finish_request(request, client_address)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 357, in finish_request
    self.RequestHandlerClass(request, client_address, self)
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\socketserver.py", line 717, in __init__
    self.handle()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 171, in handle
    self.handle_one_request()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 194, in handle_one_request
    handler.run(self.server.get_app())
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\handlers.py", line 144, in run
    self.close()
  File "D:\DjangoRestApi\venv\lib\site-packages\django\core\servers\basehttp.py", line 111, in close
    super().close()
  File "c:\users\sagar\appdata\local\programs\python\python37-32\Lib\wsgiref\simple_server.py", line 35, in close
    self.status.split(' ',1)[0], self.bytes_sent

AttributeError: 'NoneType' object has no attribute 'split'

i'm getting AttributeError: 'str' object has no attribute '_meta' this error in rest api response i sont know what is problem