code: def sendhello(self):
          try:
              # send hello
              cli_hello_msg = "<hello>\n" +\
                              "  <capabilities>\n" +\
                              "    <capability>urn:ietf:params:netconf:base:1.0</capability>\n" +\
                              "  </capabilities>\n" +\
                              "</hello>\n"
              self._cParams.set('cli_hello', cli_hello_msg)
              self._hConn.sendmsg(cli_hello_msg)
  
              # recv hello
              ser_hello_msg = self._hConn.recvmsg()
              self._cParams.set('ser_hello', ser_hello_msg)
          except:
              print 'BNClient: Call sendhello fail'
              sys.exit()
  
          
docs: end of function exchgcaps