'Helper method to perform bidirectional set differences.'

@staticmethod
def MemberDiff(data1, set1_name, data2, set2_name):

    set1 = set(data1)
    set2 = set(data2)
    diffs = []
    msg = 'Present    in    %s,    missing    in    %s:    %s'
    if (set1 != set2):
        in_set1 = (set1 - set2)
        in_set2 = (set2 - set1)
        if in_set1:
            diffs.append((msg % (set1_name, set2_name, ','.join(in_set1))))
        if in_set2:
            diffs.append((msg % (set2_name, set1_name, ','.join(in_set2))))
    return diffs
