lib/ews/soap/builders/ews_builder.rb
def dispatch_folder_id!(fid)
      if(fid[:id].is_a?(String))
        folder_id!(fid[:id], fid[:change_key])
      elsif(fid[:id].is_a?(Symbol))
        distinguished_folder_id!(fid[:id], fid[:change_key], fid[:act_as])
      else
        raise EwsBadArgumentError, "Bad argument given for a FolderId. #{fid[:id].class}"
      end
    end
def dispatch_folder_id!(fid)
      if(fid[:id].is_a?(String))
        folder_id!(fid[:id], fid[:change_key])
      elsif(fid[:id].is_a?(Symbol))
        distinguished_folder_id!(fid[:id], fid[:change_key], fid[:act_as])
      else
        raise EwsBadArgumentError, "Bad argument given for a FolderId. #{fid[:id].class}"
      end
    end
---------------------- Helpers -------------------- 
 A helper method to dispatch to a FolderId or DistinguishedFolderId correctly
 @param [Hash] fid A folder_id
   Ex: {:id => myid, :change_key => ck}