Could not find class in rqt plugin

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I am developing rqt plugin. For this purpose, I initially created a python script called my_module.py and wrote rqt code into it. It was working fine.

Later on, I renamed the script file and provided a better name. I also renamed the class name inside it. However, now rqt is not able to load it. I even tried catkin_make and sudo python setup.py install commands on it. Below is the error:

RosPluginProvider.load(rqt_robot/robot Plugin): could not find class "robotPlugin" in module "<module 'rqt_robot.my_module' from '/usr/local/lib/python2.7/dist-packages/rqt_robot/my_module.pyc'>"

Any workaround, please? As always, thank you very much. Please note that I am using Python 2.7 in ROS Indigo on Ubuntu 14.04 LTS PC.