Generator that traverses the history starting from the given commit. The following types of sorting could be used to control traversing direction:
Example:
>>> from pygit2 import Repository
>>> from pygit2 import GIT_SORT_TOPOLOGICAL, GIT_SORT_REVERSE
>>> repo = Repository('.git')
>>> for commit in repo.walk(repo.head.target, GIT_SORT_TOPOLOGICAL):
... print commit.message
>>> for commit in repo.walk(repo.head.target, GIT_SORT_TOPOLOGICAL | GIT_SORT_REVERSE):
... print commit.message
>>>