def head_ref(self):
        """
        Filters the current DataFrame to only contain those rows whose reference is HEAD.

        >>> heads_df = refs_df.head_ref

        :rtype: ReferencesDataFrame
        """
        return ReferencesDataFrame(self._engine_dataframe.getHEAD(),
                                   self._session, self._implicits)
Filters the current DataFrame to only contain those rows whose reference is HEAD.

        >>> heads_df = refs_df.head_ref

        :rtype: ReferencesDataFrame