Check if one or more columns all exist:

import pandas as pd

df = pd.DataFrame([[10, 20, 30, 40], [7, 14, 21, 28], [55, 15, 8, 12]],
                  columns=['Apple', 'Orange', 'Banana', 'Pear'],
                  index=['Basket1', 'Basket2', 'Basket3'])

if 'Apple' in df.columns:
    print("Yes")
else:
    print("No")


if set(['Apple','Orange']).issubset(df.columns):
    print("Yes")
else:
    print("No")