The poset P is graded if all of its maximalChains are the same length.
i1 : n = 5;
i2 : isGraded chain n o2 = true
i3 : isGraded booleanLattice n o3 = true
i4 : P = poset {{1,2}, {1,3}, {3,4}, {2,5}, {4, 5}};
i5 : isGraded P o5 = false