'Return the ordered merge points for a specific function.
:param int function_address: Address of the querying function.
:return: A list of sorted merge points (addresses).
:rtype: list'

def _merge_points(self, function_address):

    try:
        new_function = self.kb.functions[function_address]
    except KeyError:
        return []
    if (function_address not in self._function_merge_points):
        ordered_merge_points = CFGUtils.find_merge_points(function_address, new_function.endpoints, new_function.graph)
        self._function_merge_points[function_address] = ordered_merge_points
    return self._function_merge_points[function_address]
