rspec failing with error "block (2 levels) in

I'm trying execute some ruby script which involves sending REST calls, but its failing on below error.

An error occurred in an `after(:context)` hook.
NoMethodError: undefined method `logout_curl' for nil:NilClass
occurred at /root/343/auto/G/lib/common/rhelp.rb:110:in `block (2 levels) in <top (required)>'

I have the code block below from rhelp.rb:110

require_relative 'rest_request'
require_relative 'curl_request'    
.
.
.
config.after :all do
    $debug = true
$rest_api.logout_curl
      $curl_request.logout
$root_curl_request.logout
end

And the logout procedure is as below

require_relative 'curl_request'
.
.
.
def logout_curl
@curl_request.logout
end

Please let me know on how to rectify this error. Please note vertical 3 dots means I have only posted snippets.