<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _select_in_voltage_range(self, min_voltage=None, max_voltage=None):
 """ Selects VoltagePairs within a certain voltage range. Args: min_voltage (float):
 The minimum allowable voltage for a given step. max_voltage (float):
 The maximum allowable voltage allowable for a given step. Returns: A list of VoltagePair objects """

        min_voltage = min_voltage if min_voltage is not None \
            else self.min_voltage
        max_voltage = max_voltage if max_voltage is not None \
            else self.max_voltage
        return list(filter(lambda p: min_voltage <= p.voltage <= max_voltage,
                           self.voltage_pairs))