code: def _validate_pos(df):
      
      assert isinstance(df, pd.DataFrame)
      assert ["seqname", "position", "strand"] == df.columns.tolist()
      assert df.position.dtype == np.dtype("int64")
      assert df.strand.dtype == np.dtype("O")
      assert df.seqname.dtype == np.dtype("O")
      return df
docs: Validates the returned positional object