Return an iterator over this module's functions.
        The iterator will yield a ValueRef for each function.

def functions(self):
        """
        Return an iterator over this module's functions.
        The iterator will yield a ValueRef for each function.
        """
        it = ffi.lib.LLVMPY_ModuleFunctionsIter(self)
        return _FunctionsIterator(it, dict(module=self))