def document_type=(document_type)
      validator = EnumAttributeValidator.new('String', ["pdf", "xls", "xlsx"])
      unless validator.valid?(document_type)
        fail ArgumentError, "invalid value for 'document_type', must be one of #{validator.allowable_values}."
      end
      @document_type = document_type
    end
def document_type=(document_type)
      validator = EnumAttributeValidator.new('String', ["pdf", "xls", "xlsx"])
      unless validator.valid?(document_type)
        fail ArgumentError, "invalid value for 'document_type', must be one of #{validator.allowable_values}."
      end
      @document_type = document_type
    end
Custom attribute writer method checking allowed values (enum).
 @param [Object] document_type Object to be assigned