code: def apply(self, chart, grammar):
      for prod in grammar.productions(empty=True):
          for index in range(chart.num_leaves() + 1):
              new_edge = FeatureTreeEdge.from_production(prod, index)
              if chart.insert(new_edge, ()):
                  yield new_edge
  
imports: from time import perf_counter
  from nltk.featstruct import TYPE, FeatStruct, find_variables, unify
  from nltk.grammar import CFG, FeatStructNonterminal, Nonterminal, Production, is_nonterminal, is_terminal
  from nltk.parse.chart import BottomUpPredictCombineRule, BottomUpPredictRule, CachedTopDownPredictRule, Chart, ChartParser, EdgeI, EmptyPredictRule, FundamentalRule, LeafInitRule, SingleEdgeFundamentalRule, TopDownInitRule, TreeEdge
  from nltk.sem import logic
  from nltk.tree import Tree
label_desc: Use image node_id 1 for calling the FeatureEmptyPredictRule obj's underlying member method code with example usage: obj.apply(chart, grammar) without return types