code: def dependents(self, on_predicate=None, from_predicate=None):
      
      core = set(self.targets(on_predicate))
      dependees = defaultdict(set)
      for target in self.targets(from_predicate):
        for dependency in target.dependencies:
          if dependency in core:
            dependees[target].add(dependency)
      return dependees
docs: Returns  a map from targets that satisfy the from_predicate to targets they depend on that
        satisfy the on_predicate.
  
      :API: public