@staticmethod
def _validate_reserved(to_check: list):
    """Checks if any base key is reserved"""
    check_list = []
    for item in to_check:
        if isinstance(item, str):
            check_list.append(item)
        elif isinstance(item, list):
            check_list += item
        elif isinstance(item, dict):
            check_list = list(item.keys())
    if 'manager' in check_list or 'contract' in check_list:
        raise KeyError(
            "The reserved words 'manager' and 'contract' can not be used as base property references"
            )
