code: def prepare_post_parameters(self, post_params=None, files=None):
          
          params = []
  
          if post_params:
              params = post_params
  
          if files:
              for k, v in six.iteritems(files):
                  if not v:
                      continue
                  file_names = v if type(v) is list else [v]
                  for n in file_names:
                      with open(n, 'rb') as f:
                          filename = os.path.basename(f.name)
                          filedata = f.read()
                          mimetype = (mimetypes.guess_type(filename)[0] or
                                      'application/octet-stream')
                          params.append(
                              tuple([k, tuple([filename, filedata, mimetype])]))
  
          return params
docs: Builds form parameters.
  
          :param post_params: Normal form parameters.
          :param files: File parameters.
          :return: Form parameters with files.