code: def force_to_voltage(self, force, frequency):
          '''
          Convert a force in uN/mm to voltage.
  
          Parameters
          ----------
          force : float
              Force in **uN/mm**.
          frequency : float
              Actuation frequency.
  
          Returns
          -------
          float
              Actuation voltage to apply :data:`force` at an actuation frequency
              of :data:`frequency`.
          '''
          c_drop = self.calibration.c_drop(frequency)
  
          # if c_filler hasn't been set, assume c_filler = 0
          if self.calibration._c_filler:
              c_filler = self.calibration.c_filler(frequency)
          else:
              c_filler = 0
  
          return np.sqrt(force * 1e-9/ (0.5 * (c_drop - c_filler))f force_to_voltage(self, force, frequency):
          '''
          Convert a force in uN/mm to voltage.
  
          Parameters
          ----------
          force : float
              Force in **uN/mm**.
          frequency : float
              Actuation frequency.
  
          Returns
          -------
          float
              Actuation voltage to apply :data:`force` at an actuation frequency
              of :data:`frequency`.
          '''
          c_drop = self.calibration.c_drop(frequency)
  
          # if c_filler hasn't been set, assume c_filler = 0
          if self.calibration._c_filler:
              c_filler = self.calibration.c_filler(frequency)
          else:
              c_filler = 0
  
          return np.sqrt(force * 1e-9/ (0.5 * (c_drop - c_filler)))
docs: Convert a force in uN/mm to voltage.
  
          Parameters
          ----------
          force : float
              Force in **uN/mm**.
          frequency : float
              Actuation frequency.
  
          Returns
          -------
          float
              Actuation voltage to apply :data:`force` at an actuation frequency
              of :data:`frequency`.