def groups_per_user(group_dictionary):
    user_groups = {}
    # Go through group_dictionary
    for ___:
        # Now go through the users in the group
        for ___:
            # Now add the group to the the list of
# groups for this user, creating the entry
# in the dictionary if necessary

    return(user_groups)

print(groups_per_user({"local": ["admin", "userA"],
        "public":  ["admin", "userB"],
        "administrator": ["admin"] }))