old_contents: class FileMixins(object):
      pass
  
new_contents: class FileMixins(object):
      def show_file_configs(self, project_id):
          return self.do('GET', 'projects/{project_id}/files',
                         url_params={'project_id': project_id}
                         )
  
      def create_file_config(self, project_id, file_number, file_url, file_name=""):
          return self.do('POST', 'projects/{project_id}/files',
                         url_params={'project_id': project_id},
                         request_params={
                             'number': file_number,
                             'name': file_name,
                             'url': file_url
                         }
                         )
  
      def delete_file_config(self, project_id, file_number):
          return self.do('DELETE', 'projects/{project_id}/files/{file_number}',
                         url_params={
                             'project_id': project_id,
                             'file_number': file_number
                             }
                         )
  
      def show_file_config(self, project_id, file_number):
          return self.do('GET', 'projects/{project_id}/files/{file_number}',
                         url_params={
                             'project_id': project_id,
                             'file_number': file_number
                             }
                         )
  
      def update_file_config(self, project_id, file_number, file_url, file_name=""):
          return self.do('PUT',  'projects/{project_id}/files/{file_number}',
                         url_params={
                             'project_id': project_id,
                             'file_number': file_number
                         },
                         request_params={
                             'number': file_number,
                             'name': file_name,
                             'url': file_url
                         }
                         )
  
subject: create function about file config