How to uninstall Keras?

I have installed Keras using this command:

sudo pip install keras

It installed properly and worked fine until I tried to import application modules:

from keras.applications.vgg16 import VGG16Using Theano backend.Couldn't import dot_parser, loading of dot files will not be possible.Traceback (most recent call last):  File "<stdin>", line 1, in <module>ImportError: No module named applications.vgg16

I came across this link which recommends to uninstall Keras and directly install Keras from GitHub:

sudo pip install git+https://github.com/fchollet/keras.git

Before reinstalling Keras from GitHub, I tried to unistall Keras using this command but it throws this error:

sudo pip uninstall kerasCan't uninstall 'Keras'. No files were found to uninstall.