<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _walk_factory(self, dep_predicate):
 """Construct the right context object for managing state during a transitive walk."""

    walk = None
    if dep_predicate:
      walk = self.DepPredicateWalk(dep_predicate)
    else:
      walk = self.NoDepPredicateWalk()
    return walk