def from_signal(intf, signal)
      signal = signal.name unless signal.is_a?(String)
      self.type = "signal"
      self.interface = intf.name
      self.member = signal
      self.path = intf.object.path
      self
    end
def from_signal(intf, signal)
      signal = signal.name unless signal.is_a?(String)
      self.type = "signal"
      self.interface = intf.name
      self.member = signal
      self.path = intf.object.path
      self
    end
Sets the match rule to filter for the given _signal_ and the
 given interface _intf_.