<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _forward(self, x_dot_parameters):
 """ Helper to calculate the forward weights. """

        return forward(self._lattice, x_dot_parameters, 
                       self.state_machine.n_states)