Find variables covering the given region offset.

        :param int start:
        :return: A list of stack variables.
        :rtype:  set

def get_variables_by_offset(self, start):
        """
        Find variables covering the given region offset.

        :param int start:
        :return: A list of stack variables.
        :rtype:  set
        """

        _, container = self._get_container(start)
        if container is None:
            return []
        else:
            return container.internal_objects