[Python] Signal declaration in a separate class for use with QRunnable worker

I'm defining a Qt signal in a separate class derived from QObject for use in a QRunnable worker. The signal is emitted once by the worker as it completes. When creating two workers, the signal is received twice for each workers (hence received 4 times, if there were 3 workers, the signal would be received 9 times, etc.).

E.g. using the code below on two workers with IDs 3419 and 45435, the output is:

complete: 3419
complete: 3419
complete: 45435
complete: 45435


I suspect the signal is not correctly defined in the separate class.

import time, uuid
from qtpy.QtCore import QObject, QThreadPool, QRunnable, Signal
from qtpy.QtWidgets import QApplication, QMainWindow, QPushButton

class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.button = QPushButton("Start 2 workers")
self.button.pressed.connect(self.start)
self.setCentralWidget(self.button)
self.worker_manager = WorkerManager()

def start(self):
for i in range(2):
worker = Worker()
self.worker_manager.enqueue(worker)

class Signals(QObject):
complete = Signal(int)

class Worker(QRunnable):
signals = Signals()

def __init__(self):
super().__init__()
self.worker_id = uuid.uuid4().time_mid

def run(self):
time.sleep(0.01)
self.signals.complete.emit(self.worker_id)

class WorkerManager(QObject):

def __init__(self):
super().__init__()
self.threadpool = QThreadPool()

def enqueue(self, worker):
worker.signals.complete.connect(self.complete)
self.threadpool.start(worker)

def complete(self, worker_id):
print('complete:', worker_id)

def main():
app = QApplication([])
window = MainWindow()
window.show()
app.exec()

if __name__ == '__main__':
main()

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