742
def join(self, other):
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"""Integrate versions from other into this weave.
745
The resulting weave contains all the history of both weaves; any version you
746
could retrieve from either self or other can be retrieved from self after
749
It is illegal for the two weaves to contain different values for any version.
751
if other.numversions() == 0:
752
return # nothing to update, easy
753
raise NotImplementedError()