def _column_as_key(element):
    if isinstance(element, util.string_types):
        return element
    if hasattr(element, '__clause_element__'):
        element = element.__clause_element__()
    try:
        return element.key
    except __HOLE__:
        return None
dataset/ETHPy150Open goFrendiAsgard/kokoropy/kokoropy/packages/sqlalchemy/sql/elements.py/_column_as_key