cannot be associated with QComboBox - pyqt5

Question

button of class Main don't connect with class Qcombobox of Signals
from PyQt5.QtCore import QObject, pyqtSignal
from PyQt5.QtWidgets import *
import sys
from PyQt5 import QtGui
class Signals(QWidget):
asignal = pyqtSignal(str)
def __init__(self):
super(Signals, self).__init__()
self.setGeometry(300, 250, 400, 300)
self.ii()
self.show()
def ii(self):
vbox = QVBoxLayout()
self.combo = QComboBox()
self.combo.addItem("Python")
self.combo.addItem("Java")
self.combo.addItem("C++")
self.combo.addItem("C#")
self.combo.addItem("Ruby")
self.buttom = QPushButton("Click")
self.buttom.clicked.connect(self.windown2)
vbox.addWidget(self.combo)
vbox.addWidget(self.buttom)
self.setLayout(vbox)
def do_something(self):
self.asignal.emit(self.combo.currentText())
def windown2(self):
self.ggpp = Main()
self.ggpp.show()
class Main(QWidget):
def __init__(self):
super(Main, self).__init__()
self.setGeometry(500,150, 600, 300)
vbox1 = QVBoxLayout()
self.buttom1 = QPushButton("Click")
self.buttom1.clicked.connect(self.coso1)
vbox1.addWidget(self.buttom1)
self.setLayout(vbox1)
def coso1(self):
s = Signals()
s.asignal.connect(lambda sig: print("self.combo.currentText()>>>>>" + sig))
s.do_something()
if __name__ == '__main__':
app = QApplication(sys.argv)
nals = Signals()
nals.show()
sys.exit(app.exec())

Answer 1

What you see happens because you're not using the existing instance of Signals, but you're creating a new one each time the button is clicked.
In your case, you could add a reference to the instance as an argument when you create the new window, so that you can correctly connect to its signal.
class Signals(QWidget):
# ...
def windown2(self):
self.ggpp = Main(self)
self.ggpp.show()
class Main(QWidget):
def __init__(self, signals):
super(Main, self).__init__()
self.signals = signals
self.signals.asignal.connect(self.coso1)
self.setGeometry(500,150, 600, 300)
vbox1 = QVBoxLayout()
self.buttom1 = QPushButton("Click")
self.buttom1.clicked.connect(self.signals.do_something)
vbox1.addWidget(self.buttom1)
self.setLayout(vbox1)
def coso1(self, sig):
print("self.combo.currentText()>>>>>" + sig)