code: def _get_from(self, required_for=None):
          
          line = self.next_line()
          if line is None:
              return None
          elif line.startswith(b'from '):
              return line[len(b'from '):]
          elif required_for:
              self.abort(errors.MissingSection, required_for, 'from')
          else:
              self.push_line(line)
              return None
docs: Parse a from section.