code: def _headers(self, name, is_file=False):
          
          value = self._files[name] if is_file else self._data[name]
          _boundary = self.boundary.encode("utf-8") if isinstance(self.boundary, unicode) else urllib.quote_plus(self.boundary)
     
          headers = ["--%s" % _boundary]
  
          if is_file:
              disposition = 'form-data; name="%s"; filename="%s"' % (name, os.path.basename(value))
          else:
              disposition = 'form-data; name="%s"' % name
  
          headers.append("Content-Disposition: %s" % disposition)
  
          if is_file:
              file_type = self._file_type(name)
          else:
              file_type = "text/plain; charset=utf-8"
  
          headers.append("Content-Type: %s" % file_type)
  
          if is_file:
              headers.append("Content-Length: %i" % self._file_size(name))
          else:
              headers.append("Content-Length: %i" % len(value))
  
          headers.append("")
          headers.append("")
  
          return "\r\n".join(headers)
docs: Returns the header of the encoding of this parameter.
          
          Args:
              name (str): Field name
          
          Kwargs:
              is_file (bool): If true, this is a file field
          
          Returns:
              array. Headers