Helper to merge which handles merging one value.
(self, old, new)
| 119 | return old |
| 120 | |
| 121 | def _merge(self, old, new): |
| 122 | """Helper to merge which handles merging one value.""" |
| 123 | if old is None: |
| 124 | return new |
| 125 | elif new is not None and old is not new: |
| 126 | raise ValueError("Incompatible values: %s != %s" % (old, new)) |
| 127 | return old |
| 128 | |
| 129 | def _deep_tuple(self, x): |
| 130 | """Converts lists of lists to tuples of tuples.""" |