docs: def to_unit_velocity_acceleration(self, va):
          """ Convert velocities/accelerations to units of UnitConverter.
  
          Converts velocity/ies and/or acceleration/s from units of motor
          pitch per second (or second squared) to that of this
          UnitConverter.
  
          Parameters
          ----------
          va : int, float, or iterable of ints and floats
              The velocities/accelerations to convert.
  
          Returns
          -------
          converted_va : float or list of floats
              The converted velocities/accelerations.
  
          """
          if isinstance(va, collections.Iterable):
              return [(x / self._va_to_motor) for x in va]
          else:
              return va / self._va_to_motor