class_docstr: Abstract base class for all IBM models
class_docstr_tok: ["Abstract","base","class","for","all","IBM","models"]
code: def prob_of_alignments(self, alignments):
      probability = 0
      for alignment_info in alignments:
          probability += self.prob_t_a_given_s(alignment_info)
      return probability
  
imports: from bisect import insort_left
  from collections import defaultdict
  from copy import deepcopy
  from math import ceil
label_desc: Use image node_id 12 for calling the IBMModel obj's underlying member method code with example usage: obj.prob_of_alignments(alignments) and returns: probability