code: def _iterate_first(
      first, second, bindings, used, skipped, finalize_method, debug
  ):
      """
      This method facilitates movement through the terms of 'self'
      """
      debug.line(f"unify({first},{second}) {bindings}")
  
      if not len(first) or not len(
          second
      ):  # if no more recursions can be performed
          return finalize_method(
              first, second, bindings, used, skipped, debug
          )
      else:
          # explore this 'self' atom
          result = _iterate_second(
              first,
              second,
              bindings,
              used,
              skipped,
              finalize_method,
              debug + 1,
          )
  
          # skip this possible 'self' atom
          newskipped = (skipped[0] + [first[0]], skipped[1])
          result += _iterate_first(
              first[1:],
              second,
              bindings,
              used,
              newskipped,
              finalize_method,
              debug + 1,
          )
  
          try:
              newbindings, newused, unused = _unify_terms(
                  first[0], second[0], bindings, used
              )
              # Unification found, so progress with this line of unification
              # put skipped and unused terms back into play for later unification.
              newfirst = first[1:] + skipped[0] + unused[0]
              newsecond = second[1:] + skipped[1] + unused[1]
              result += _iterate_first(
                  newfirst,
                  newsecond,
                  newbindings,
                  newused,
                  ([], []),
                  finalize_method,
                  debug + 1,
              )
          except BindingException:
              # the atoms could not be unified,
              pass
  
          return result
  
imports: import operator
  from collections import defaultdict
  from functools import reduce
  from nltk.inference.api import BaseProverCommand, Prover
  from nltk.sem import skolemize
  from nltk.sem.logic import AndExpression, ApplicationExpression, EqualityExpression, Expression, IndividualVariableExpression, NegatedExpression, OrExpression, Variable, VariableExpression, is_indvar, unique_variable
label_desc: Use image node_id 1 for calling a global function with example usage: _iterate_first(first, second, bindings, used, skipped, finalize_method, debug) and returns: finalize_method, result