How check if an email exist without send in Ruby? Use of email_veracity_checker

I’m trying to create a ruby script that checks the real existence of
some e-mail. I’ve found email_veracity_checker but I don’t understand
how implement a simple test. The “Readme” file only says the following:

Add following entry in your config/environment.rb

config.gem ‘email_veracity_checker’, :lib => “email_check”

How to use:

#first param is user email address
#second sender address
#third param is domain address

#Note: It’s not sending email, at the end point they quit connection.“[email protected]”,“[email protected]”,“”).valid?

It’s return can be true or false"

Can someone help me? Thanks