new_contents: """A dual wound coil which consists of two coils."""
  from mpf.core.system_wide_device import SystemWideDevice
  
  
  class DualWoundCoil(SystemWideDevice):
  
      """An instance of a dual wound coil which consists of two coils."""
  
      config_section = "dual_wound_coils"  # String of the config section name
      collection = "dual_wound_coils"  # String name of the collection
      class_label = "dual_wound_coil"  # String of the friendly name of the device class
  
      def __init__(self, machine, name):
          """Initialise a dual wound coil."""
          super().__init__(machine, name)
          # Add this device to the coil section
          self.machine.coils[name] = self
  
      def enable(self, **kwargs):
          """Enable a dual wound coil.
  
          Pulse main coil and enable hold coil.
          """
          del kwargs
          self.config['main_coil'].pulse()
          self.config['hold_coil'].enable()
  
      def disable(self, **kwargs):
          """Disable a driver."""
          del kwargs
          self.config['main_coil'].disable()
          self.config['hold_coil'].disable()
  
      def pulse(self, milliseconds: int=None, power: float=None, **kwargs):
          """Pulse this driver.
  
          Args:
              milliseconds: The number of milliseconds the driver should be
                  enabled for. If no value is provided, the driver will be
                  enabled for the value specified in the config dictionary.
              power: A multiplier that will be applied to the default pulse time,
                  typically a float between 0.0 and 1.0. (Note this is can only be used
                  if milliseconds is also specified.)
          """
          del kwargs
          self.config['main_coil'].pulse(milliseconds, power)
          self.config['hold_coil'].pulse(milliseconds, power)
  
subject: add simple dual wound coil