<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def first(self):
 """Returns the first module procedure embedded in the interface that has a valid instance of a CodeElement. """

        if self._first is None:
            for target in self.targets:
                if target is not None:
                    self._first = target
                    break
            else:
                self._first = False

        return self._first