mean_employed_60 = credit_report[(credit_report['dob_years']>=60)  & (credit_report['days_employed'] < 20000)]['days_employed'].mean()
credit_report['days_employed'] = credit_report[(credit_report['dob_years']>=60)]['days_employed'].fillna(median_employed_60)
#credit_report[(credit_report['dob_years']>=60)]['days_employed'].fillna(mean_employed_60)
print(credit_report.head(15))