parameters: (self, option, channel, orderer_url, time_out="90s")
return_statement: return res
docstring: Fetch a specified block, writing it to a file e.g. <channelID>.block.
          params:
              option: block option newest|oldest|config|(block number).
              channel: channel id.
              orderer_url: Ordering service endpoint.
docstring_summary: Fetch a specified block, writing it to a file e.g. <channelID>.block.
          params:
              option: block option newest|oldest|config|(block number).
              channel: channel id.
              orderer_url: Ordering service endpoint.
docstring_tokens: Fetch a specified block writing it to a file e . g . <channelID > . block . params : option : block option newest|oldest|config| ( block number ) . channel : channel id . orderer_url : Ordering service endpoint .
function: def fetch(self, option, channel, orderer_url, time_out="90s"):
          """
          Fetch a specified block, writing it to a file e.g. <channelID>.block.
          params:
              option: block option newest|oldest|config|(block number).
              channel: channel id.
              orderer_url: Ordering service endpoint.
          """
          try:
              res = os.system("{} channel fetch {} -c {} -o {} --timeout {}".format(
                  self.peer, option, channel, orderer_url, time_out))
          except Exception as e:
              err_msg = "fetch a specified block failed {}!".format(e)
              raise Exception(err_msg)
          res = res >> 8
          return res
function_tokens: def fetch ( self , option , channel , orderer_url , time_out = "90s" ) : try : res = os . system ( "{} channel fetch {} -c {} -o {} --timeout {}" . format ( self . peer , option , channel , orderer_url , time_out ) ) except Exception as e : err_msg = "fetch a specified block failed {}!" . format ( e ) raise Exception ( err_msg ) res = res >> 8 return res