<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_value(self, var_name):
 """Return the value of a given variable. Parameters var_name : str The name of the variable whose value should be returned Returns ------- value : float The value of the given variable in the current state """

        if var_name in self.outside_name_map:
            var_name = self.outside_name_map[var_name]
        species_idx = self.species_name_map[var_name]
        return self.state[species_idx]