Schedule a function handler to be called just before completion.

        This is used for handling function bodies, which must be deferred
        because code later in the file might modify the global scope. When
        `callable` is called, the scope at the time this is called will be
        restored, however it will contain any new bindings added to it.

def deferFunction(self, callable):
        """
        Schedule a function handler to be called just before completion.

        This is used for handling function bodies, which must be deferred
        because code later in the file might modify the global scope. When
        `callable` is called, the scope at the time this is called will be
        restored, however it will contain any new bindings added to it.
        """
        self._deferredFunctions.append((callable, self.scopeStack[:], self.offset))