@property<EOL><INDENT>def cardinality(self):<DEDENT>
cardinality = <NUM_LIT:0><EOL>for si in self._si_set:<EOL><INDENT>cardinality += si.cardinality<EOL><DEDENT>return cardinality<EOL>
This is an over-approximation of the cardinality of this DSIS.

:return: