there are two Pandas dataframes: rzd client_id rzd_revenue 0 111 1093 1 112 2810 2 113 10283 3 114 5774 4 115 981 auto client_id auto_revenue 0 113 57483 1 114 83 2 115 912 3 116 4834 4 117 98 Create a new dataframe joined and merge these 2 dataframes inside it

def merge_df(df1, df2):
    # Combine the dataframes on client_id
    return df1.merge(df2, on='client_id')

merge_df(rzd, auto)