print(df)

>>
+---------+---------+
|       ID|     Type|
+---------+---------+
|      AAA|        A|
|      BBB|        B|
|      CCC|        B|
|      DDD|        A|
|      EEE|        B|
|      FFF|        A|
|      GGG|        B|
+---------+---------+

X = 2
new_df = do_something(df, X)
print(df)

>>
+---------+---------+
|       ID|     Type|
+---------+---------+
|      AAA|        A|
|      DDD|        A|
|      BBB|        B|
|      CCC|        B|
+---------+---------+