def requires(params)
      params.each { |k, v|
        if v == nil || v.to_s.length == 0
          raise InvalidParamError.new "#{k} is a required parameter, it cannot be nil or empty"
        end
      }
    end
def requires(params)
      params.each { |k, v|
        if v == nil || v.to_s.length == 0
          raise InvalidParamError.new "#{k} is a required parameter, it cannot be nil or empty"
        end
      }
    end
Initializer to create global @config object

 @param config [Hash] Pass config object, including your DataSift username,
   API key and any other custom config parameters
 Ensure parameters have been set

 @param params [Hash] Hash of parameters you need to check exist and are
   non-null values