Unchecked variable in TensorIndexType.__new__ might be error prone

[r.du...@gmail.com]

Dear developers of module tensor

The variable name in TensorIndexType.__new__ is only checked against string_types:

https://github.com/sympy/sympy/blob/master/sympy/tensor/tensor.py#L1597

To me this seems error-prone if name is not a symbol.

You might want to proceed as for TensorIndex.__new__
https://github.com/sympy/sympy/blob/master/sympy/tensor/tensor.py#L1828

Best regards
ric