def get_entity_group_version(key):
eg = EntityGroup.key_for_entity_group(key).get()<EOL>if eg:<EOL><INDENT>return eg.version<EOL><DEDENT>else:<EOL><INDENT>return None<EOL><DEDENT>
Return the version of the entity group containing key.

    Args:
      key: a key for an entity group whose __entity_group__ key you want.

    Returns:
      The version of the entity group containing key. This version is
      guaranteed to increase on every change to the entity group. The version
      may increase even in the absence of user-visible changes to the entity
      group. May return None if the entity group was never written to.

      On non-HR datatores, this function returns None.