def get_source(self):
return self._payload.get_source()<EOL>
Gets the ``Resource`` of the source of this asset.

        The source is the original owner of the copyright of this asset
        and may differ from the creator of this asset. The source for a
        published book written by Margaret Mitchell would be Macmillan.
        The source for an unpublished painting by Arthur Goodwin would
        be Arthur Goodwin.

        return: (osid.resource.Resource) - the source
        *compliance: mandatory -- This method must be implemented.*