Unable to register generator-mocha

[hemanth]

yo -v => 1.0.0-beta.4

See a list of all available generators with npm search yeoman-generator

Unable to register generator-mocha/app/index.js (Error: Cannot assign to read only property 'name' of function (args, options) {
  this.option('assert-framework', {
    type: String,
    defaults: 'chai',
    desc: 'Choose your prefered assertion library'
  });

  this.option('assert-style', {
    desc: 'Choose the asssert style you wish to use (assert, expect, should). Only enabled with chai.',
    type: String,
    defaults: 'expect'
  });

  this.option('ui', {
    desc: 'Choose your style of DSL (bdd, tdd, qunit, or exports)',
    type: String,
    defaults: 'bdd'
  });

  this.directory('.', 'test');
})
Unable to register generator-mocha/app/index.js (Error: Cannot assign to read only property 'name' of function (args, options) {
  this.option('assert-framework', {
    type: String,
    defaults: 'chai',
    desc: 'Choose your prefered assertion library'
  });

  this.option('assert-style', {
    desc: 'Choose the asssert style you wish to use (assert, expect, should). Only enabled with chai.',
    type: String,
    defaults: 'expect'
  });

  this.option('ui', {
    desc: 'Choose your style of DSL (bdd, tdd, qunit, or exports)',
    type: String,
    defaults: 'bdd'
  });

  this.directory('.', 'test');
})
Usage: yo GENERATOR [args] [options],,General options:,  -h, --help     # Print generator's options and usage,  -f, --force    # Overwrite files that already exist,,Please choose a generator below.,,,Generator,  generator,,Mocha,  mocha:generator,,Webapp,  webapp:app

Error: Cannot assign to read only property 'name' of function 

Not able to figure out...