code: public function loadCredentials($credentials)
  	{
  		$this->access_key = $credentials['access_key'];
  		$this->username = $credentials['username'];
  		$this->password = $credentials['password'];
  		$this->account_number = $credentials['account_number'];
  	}
docs: Load UPS.com credentials from the config file
  located at beaudierman/ups/src/config/config.php
  
  @param credentials array
  
  @return void