(elems)
| 116 | |
| 117 | |
| 118 | def _perm4(elems): |
| 119 | for x in elems: |
| 120 | for y in elems: |
| 121 | if y == x: |
| 122 | continue |
| 123 | for z in elems: |
| 124 | if z in (x, y): |
| 125 | continue |
| 126 | for t in elems: |
| 127 | if t not in (x, y, z): |
| 128 | yield x, y, z, t |
| 129 | |
| 130 | |
| 131 | def perm4(elems): |