def extract_paging(response)
      paging            = response.to_h['paging']
      next_page_url     = paging && paging['next']      # gives nil when any one of the keys doens't exist
      previous_page_url = paging && paging['previous']  # can be replaced with Hash#dig for ruby >= 2.3.0
      @paging_next      = extract_endpoint_from(next_page_url)
      @paging_previous  = extract_endpoint_from(previous_page_url)
    end
def extract_paging(response)
      paging            = response.to_h['paging']
      next_page_url     = paging && paging['next']      # gives nil when any one of the keys doens't exist
      previous_page_url = paging && paging['previous']  # can be replaced with Hash#dig for ruby >= 2.3.0
      @paging_next      = extract_endpoint_from(next_page_url)
      @paging_previous  = extract_endpoint_from(previous_page_url)
    end
Internal: given an event response, pull and store the paging keys

 response - a Mailgun::Response object

 Return is irrelevant.