import pandas as pd
              import numpy as np
              raw_data = {'name': ['Willard Morris', 'Al Jennings', 'Omar Mullins', 'Spencer McDaniel'],
                      'age': [20, 19, 22, 21],
                      'favorite_color': ['blue', 'red', 'yellow', "green"],
                      'grade': [88, 92, 95, 70]}
              df = pd.DataFrame(raw_data, index = ['Willard Morris', 'Al Jennings', 'Omar Mullins', 'Spencer McDaniel'])
              df
              df.columns = [x.strip().replace('_', '_TEST_') for x in df.columns]
              df.head()