def get_source_id(self):
return Id(self._my_map['<STR_LIT>'])<EOL>
Gets the Resource Id 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        The source for an unpublished painting by Arthur Goodwin would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.

        An Asset is Sourceable and also contains a provider identity.
        The provider is the entity that makes this digital asset
        available in this repository but may or may not be the publisher
        of the contents depicted in the asset. For example, a map
        published by Ticknor and Fields in 1848 may have a provider of
        Library of Congress and a source of Ticknor and Fields. If
        copied from a repository at Middlebury College, the provider
        would be Middlebury College and a source of Ticknor and Fields.

        return: (osid.id.Id) - the source Id
        compliance: mandatory - This method must be implemented.