code: def _attempt_proof_n_atom(
      self, current, context, agenda, accessible_vars, atoms, debug
  ):
      # Check if the branch is closed.  Return 'True' if it is
      if (current.term, False) in atoms:
          debug.line("CLOSED", 1)
          return True
  
      if context:
          if isinstance(context.term, NegatedExpression):
              current = current.negate()
          agenda.put(context(current).simplify())
          return self._attempt_proof(
              agenda, accessible_vars, atoms, debug + 1
          )
      else:
          # mark all AllExpressions as 'not exhausted' into the agenda since we are (potentially) adding new accessible vars
          agenda.mark_alls_fresh()
          return self._attempt_proof(
              agenda,
              accessible_vars | set(current.term.args),
              atoms | {(current.term, True)},
              debug + 1,
          )
  
imports: from nltk.inference.api import BaseProverCommand, Prover
  from nltk.internals import Counter
  from nltk.sem.logic import AbstractVariableExpression, AllExpression, AndExpression, ApplicationExpression, EqualityExpression, ExistsExpression, Expression, FunctionVariableExpression, IffExpression, ImpExpression, LambdaExpression, NegatedExpression, OrExpression, Variable, VariableExpression, unique_variable
label_desc: Use image node_id 4 for calling the TableauProver obj's underlying member method code with example usage: obj._attempt_proof_n_atom(current, context, agenda, accessible_vars, atoms, debug) and returns: True, self, self