<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def segment_common_items(segment_id):
 """ Returns all the common items in a segment. """

    df = data.common_items
    return (
        df
        .loc[str(segment_id)]
        .reset_index(drop=1)
        .drop(columns=["itemOccurrences"])
    )