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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def step_forward(self):
 """Updates state variables with computed tendencies. Calls the :func:`compute` method to get current tendencies for all process states. Multiplied with the timestep and added up to the state variables is updating all model states. :Example: :: 0 1 """

        tenddict = self.compute()
        #  Total tendency is applied as an explicit forward timestep
        # (already accounting properly for order of operations in compute() )
        for varname, tend in tenddict.items():
            self.state[varname] += tend * self.timestep
        # Update all time counters for this and all subprocesses in the tree
        #  Also pass diagnostics up the process tree
        for name, proc, level in walk.walk_processes(self, ignoreFlag=True):
            if proc.time['active_now']:
                proc._update_time()