def queen_constraint(A, a, B, b):
    """Constraint is satisfied (true) if A, B are really the same variable,
    or if they are not in the same row, down diagonal, or up diagonal."""
    return A == B or (a != b and A + a != B + b and A - a != B - b)
def queen_constraint(A, a, B, b):
    """Constraint is satisfied (true) if A, B are really the same variable,
    or if they are not in the same row, down diagonal, or up diagonal."""
    return A == B or (a != b and A + a != B + b and A - a != B - b)
def queen_constraint ( A , a , B , b ) : return A == B or ( a != b and A + a != B + b and A - a != B - b )
Constraint is satisfied (true) if A, B are really the same variable,
    or if they are not in the same row, down diagonal, or up diagonal.
Constraint is satisfied ( true ) if A B are really the same variable or if they are not in the same row down diagonal or up diagonal .