def get_distance_set(self):
<EOL>if self._kwargs['<STR_LIT>'] not in ['<STR_LIT>']:<EOL><INDENT>raise errors.IllegalState()<EOL><DEDENT>return self._kwargs['<STR_LIT>']<EOL>
Gets the set of acceptable distance values.

        return: (osid.mapping.Distance) - a set of values or an empty
                array if not restricted
        raise:  IllegalState - syntax is not a ``DISTANCE``
        *compliance: mandatory -- This method must be implemented.*