How to use the babylon/lib/tokenizer.default.prototype function in babylon

var Parser = require('babylon/lib/parser').default;
var _tokenizerTypes = require('babylon/lib/tokenizer/types');
var Tokenizer = require('babylon/lib/tokenizer').default;

// Add tokenizer type.
_tokenizerTypes.types.questionDot = new _tokenizerTypes.TokenType("?.", { beforeExpr: true });
_tokenizerTypes.types.questionParenL = new _tokenizerTypes.TokenType("?(", { beforeExpr: true, startsExpr: true });

// Tokenize "?(" and "?.".
const originalGetTokenFromCode = Tokenizer.prototype.getTokenFromCode;
Tokenizer.prototype.getTokenFromCode = function getTokenFromCode(code) {
  if (code === 63) {
    var next = this.input.charCodeAt(this.state.pos + 1);
    switch (next) {
      case 40:
        this.state.pos += 2;
        return this.finishToken(_tokenizerTypes.types.questionParenL);
      case 46:
        this.state.pos += 2;
        return this.finishToken(_tokenizerTypes.types.questionDot);
    }
  }
  return originalGetTokenFromCode.apply(this, arguments);
};

// Parse SafeMemberExpression.

var Parser = require('babylon/lib/parser').default;
var _tokenizerTypes = require('babylon/lib/tokenizer/types');
var Tokenizer = require('babylon/lib/tokenizer').default;

// Add tokenizer type.
_tokenizerTypes.types.questionDot = new _tokenizerTypes.TokenType("?.", { beforeExpr: true });
_tokenizerTypes.types.questionParenL = new _tokenizerTypes.TokenType("?(", { beforeExpr: true, startsExpr: true });

// Tokenize "?(" and "?.".
const originalGetTokenFromCode = Tokenizer.prototype.getTokenFromCode;
Tokenizer.prototype.getTokenFromCode = function getTokenFromCode(code) {
  if (code === 63) {
    var next = this.input.charCodeAt(this.state.pos + 1);
    switch (next) {
      case 40:
        this.state.pos += 2;
        return this.finishToken(_tokenizerTypes.types.questionParenL);
      case 46:
        this.state.pos += 2;
        return this.finishToken(_tokenizerTypes.types.questionDot);
    }
  }
  return originalGetTokenFromCode.apply(this, arguments);
};

// Parse SafeMemberExpression.
const originalParseSubscripts = Parser.prototype.parseSubscripts;