Establish a connection to the TDT PA5 attenuator

def connect_attenuator(self, connect=True):
        """Establish a connection to the TDT PA5 attenuator"""
        if connect:
            try:
                pa5 = win32com.client.Dispatch("PA5.x")
                success = pa5.ConnectPA5('GB', 1)
                if success == 1:
                    print 'Connection to PA5 attenuator established'
                    pass
                else:
                    print 'Connection to PA5 attenuator failed'
                    errmsg = pa5.GetError()
                    print u"Error: ", errmsg
                    raise Exception(u"Attenuator connection failed")
            except:
                print "Error connecting to attenuator"
                pa5 = None

            self.attenuator = pa5
        else:
            # if there is an attenuator, make sure it is set to 0 before disconnecting
            if self.attenuator:
                self.attenuator.setAtten(0)
            self.attenuator = None
        return self.attenuator