ModuleNotFoundError: No module named 'readchar' code example

Example 1: ModuleNotFoundError: No module named 'seaborn'

#python 1
pip install seaborn
#python 3
pip install seaborn

Example 2: ModuleNotFoundError: No module named 'sklearn'

#for python 1
pip install -U scikit-learn scipy matplotlib
#for python 3
pip3 install -U scikit-learn scipy matplotlib