def where(self, f, indices=False):
idcs = np.where(self.map(f))[<NUM_LIT:0>]<EOL>return idcs if indices else self.labels[idcs]<EOL>
obj.where(f) yields a list of vertex labels l such that f(p[l]) yields True, where p is the
  properties value for the vertex-set obj (i.e., p[l] is the property map for the vertex
  with label l. The function f should operate on a dict p which is identical to that passed
  to the method obj.properties.map().
The optional third parameter indices (default: False) may be set to True to indicate that
indices should be returned instead of labels.