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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def find_dependencies(self, dependent_rev, recurse=None):
 """Find all dependencies of the given revision, recursively traversing the dependency tree if requested. """

        if recurse is None:
            recurse = self.options.recurse

        try:
            dependent = self.get_commit(dependent_rev)
        except InvalidCommitish as e:
            abort(e.message())

        self.todo.append(dependent)
        self.todo_d[dependent.hex] = True

        first_time = True

        while self.todo:
            sha1s = [commit.hex[:8] for commit in self.todo]
            if first_time:
                self.logger.info("Initial TODO list: %s" % " ".join(sha1s))
                first_time = False
            else:
                self.logger.info("  TODO list now: %s" % " ".join(sha1s))
            dependent = self.todo.pop(0)
            dependent_sha1 = dependent.hex
            del self.todo_d[dependent_sha1]
            self.logger.info("  Processing %s from TODO list" %
                              dependent_sha1[:8])

            if dependent_sha1 in self.done_d:
                self.logger.info("  %s already done previously" %
                                  dependent_sha1)
                continue

            self.notify_listeners('new_commit', dependent)

            parent = dependent.parents[0]
            self.find_dependencies_with_parent(dependent, parent)
            self.done.append(dependent_sha1)
            self.done_d[dependent_sha1] = True
            self.logger.info("  Found all dependencies for %s" %
                              dependent_sha1[:8])
            # A commit won't have any dependencies if it only added new files
            dependencies = self.dependencies.get(dependent_sha1, {})
            self.notify_listeners('dependent_done', dependent, dependencies)

        self.logger.info("Finished processing TODO list")
        self.notify_listeners('all_done')