Building a Complete Mapping Application using Python and QGIS - Building Mapping Applications with QGIS - page 248

The mapTools.py module
We used mapTools.py in the Lex application to define our various map tools separately
from the main program. We're going to do the same here. For now, though, our
mapTools.py module is almost empty:
from qgis.core import *
from qgis.gui import *
from PyQt4.QtGui import *
from PyQt4.QtCore import *
from constants import *
Obviously, we'll be adding to this as we start to implement our various map tools, but for
now, this is enough.