data file path in a gem

[Erwin]

I am trying to access a data list from inside a gem code, how should I
set the file path ..

here is my gem file structure :

>> my_extension
--- my_extension.gemspec
--- Gemfile
--- Gemfile.lock
>> lib
>> my_extension
--- code_a.rb
--- code_b.rb
--- code_c.rb
--- my_extension.rb
>> my_data
--- data.yml

from inside code_a.rb, I am trying to load an array from the
data.yml : data = YAML::load(File.open("data.yml"))
how should I set the path ??

thanks for feedback