<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def has_substring(self, substring):
 """ Construct a Filter matching values containing ``substring``. Parameters substring : str Sub-string against which to compare values produced by ``self``. Returns ------- matches : Filter Filter returning True for all sid/date pairs for which ``self`` produces a string containing ``substring``. """

        return ArrayPredicate(
            term=self,
            op=LabelArray.has_substring,
            opargs=(substring,),
        )