How to synchronize two dataframes?

Question

i have two dataframes that have one same column. For example:

>> df1
>> pi_id     C          V          P
    1       12         10         120
    2        5          4          20
    3        2          2           4

>> df2
>> pi_id     T
    1        5
    1        6
    1        7
    2        8
    2        9
    3        10
    3        11

and my expected output is:

>> df3
>> pi_id      T        C          V          P
    1         5        12         10        120
    1         6        12         10        120
    1         7        12         10        120
    2         8         5          4         20
    2         9         5          4         20
    3        11         2          2          4
    3        11         2          2          4

Which would be the best method to do that on python?