code: def _categorize_expression(self, current):
      if isinstance(current, NegatedExpression):
          return self._categorize_NegatedExpression(current)
      elif isinstance(current, FunctionVariableExpression):
          return Categories.PROP
      elif TableauProver.is_atom(current):
          return Categories.ATOM
      elif isinstance(current, AllExpression):
          return Categories.ALL
      elif isinstance(current, AndExpression):
          return Categories.AND
      elif isinstance(current, OrExpression):
          return Categories.OR
      elif isinstance(current, ImpExpression):
          return Categories.IMP
      elif isinstance(current, IffExpression):
          return Categories.IFF
      elif isinstance(current, EqualityExpression):
          return Categories.EQ
      elif isinstance(current, ExistsExpression):
          return Categories.EXISTS
      elif isinstance(current, ApplicationExpression):
          return Categories.APP
      else:
          raise ProverParseError(
              "cannot categorize %s" % current.__class__.__name__
          )
  
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 11 for calling the Agenda obj's underlying member method code with example usage: obj._categorize_expression(current) and returns: self, Categories, Categories, Categories, Categories, Categories, Categories, Categories, Categories, Categories, Categories