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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def domain_match(A, B):
 """Return True if domain A domain-matches domain B, according to RFC 2965. A and B may be host domain names or IP addresses. RFC 2965, section 1: Host names can be specified either as an IP address or a HDN string. Sometimes we compare one host name with another. (Such comparisons SHALL be case-insensitive.) Host A's name domain-matches host B's if * their host name strings string-compare equal; or * A is a HDN string and has the form NB, where N is a non-empty name string, B has the form .B', and B' is a HDN string. (So, x.y.com domain-matches .Y.com but not Y.com.) Note that domain-match is not a commutative operation: a.b.c.com domain-matches .c.com, but not the reverse. """

    # Note that, if A or B are IP addresses, the only relevant part of the
    # definition of the domain-match algorithm is the direct string-compare.
    A = A.lower()
    B = B.lower()
    if A == B:
        return True
    if not is_HDN(A):
        return False
    i = A.rfind(B)
    if i == -1 or i == 0:
        # A does not have form NB, or N is the empty string
        return False
    if not B.startswith("."):
        return False
    if not is_HDN(B[1:]):
        return False
    return True