def is_base_complement(c1, c2):
    """Returns true if c1 is a watson-crick complement of c2

    args:
        c1 -- char
        c2 -- char
    returns:
        bool -- True if is complement, false otherwise
    """
    if c1 == "A":
        return c2 == "U"
    elif c1 == "U":
        return c2 == "G" or c2 == "A"
    elif c1 == "G":
        return c2 == "C" or c2 == "U"
    elif c1 == "C":
        return c2 == "G"
    return False