Alina

def total_income_group(total_income):
    if total_income <= 30000:
        return 'E'
    if total_income <= 50000:
        return 'D'
    if total_income <= 200000:
        return 'C'
    if total_income <= 1000000:
        return 'B'
    else:
        return 'A'

loan.apply(lambda total_income: total_income_group(total_income), axis=1)