This example shows how to emit signal from a function at module level , signal in turn is connected to SLOT in the class that can perform some action.

emitSignal_1.py

from PyQt4.QtCore import pyqtSignal, pyqtSlot
from PyQt4.QtGui import QWidget, QApplication
from PyQt4 import QtCore
import sys

_qObject = QtCore.QObject()


class SomeOtherClass(QWidget):

    # this is my UI class

    def __init__(self, parent=None):
        super(SomeOtherClass, self).__init__(parent)

        # Initialise the Class and connect signal to slot
        QtCore.QObject.connect(_qObject, QtCore.SIGNAL("error_occured"), self.thrown_error)


    def thrown_error(self, my_err):
        #Do Stuff with the Exception
        print(type(my_err), my_err)


def makeError():
    try:
        print 1/0
    except ZeroDivisionError, ex:
        QtCore.QObject.emit(_qObject, QtCore.SIGNAL("error_occured"), str(ex))

app = QApplication(sys.argv)
win = SomeOtherClass()
makeError()
win.show()
sys.exit(app.exec_())