def object_to_http_body(model)
      return model if model.nil? || model.is_a?(String)
      local_body = nil
      if model.is_a?(Array)
        local_body = model.map{|m| object_to_hash(m) }
      else
        local_body = object_to_hash(model)
      end
      local_body.to_json
    end
def object_to_http_body(model)
      return model if model.nil? || model.is_a?(String)
      local_body = nil
      if model.is_a?(Array)
        local_body = model.map{|m| object_to_hash(m) }
      else
        local_body = object_to_hash(model)
      end
      local_body.to_json
    end
Convert object (array, hash, object, etc) to JSON string.
 @param [Object] model object to be converted into JSON string
 @return [String] JSON string representation of the object