'Check that the object has a given member variable.
:param member: the member variable to check for
:param error_msg: the message for an error if the member is missing
:raise ObjectFormatException: with the given error_msg if member is
missing or is None'

def _check_has_member(self, member, error_msg):

    if (getattr(self, member, None) is None):
        raise ObjectFormatException(error_msg)
