<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def must_contain(self, value, q, strict=False):
 """if value must contain q"""

        if value is not None:
            if value.find(q) != -1:
                return
        self.shout('Value %r does not contain %r', strict, value, q)