@classmethod
def signed_from_df(cls, df, sign_dict=None, flattening_method=None,
    weight_mapping=None):
    """Create a signed graph from a pandas DataFrame."""
    net = cls.from_df(df)
    return net.to_signed_graph(sign_dict=sign_dict, flattening_method=
        flattening_method, weight_mapping=weight_mapping)
