docs: def native(self, value, context=None):
  		"""Convert a foreign value to a native boolean."""
  		
  		value = super().native(value, context)
  		
  		if self.none and (value is None):
  			return None
  		
  		try:
  			value = value.lower()
  		except AttributeError:
  			return bool(value)
  		
  		if value in self.truthy:
  			return True
  		
  		if value in self.falsy:
  			return False
  		
  		raise Concern("Unable to convert {0!r} to a boolean value.", value)