code: async def callproc(self, procname, args=()):
          
          conn = self._get_db()
          if self._echo:
              logger.info("CALL %s", procname)
              logger.info("%r", args)
  
          for index, arg in enumerate(args):
              q = "SET @_%s_%d=%s" % (procname, index, conn.escape(arg))
              await self._query(q)
              await self.nextset()
  
          _args = ','.join('@_%s_%d' % (procname, i) for i in range(len(args)))
          q = "CALL %s(%s)" % (procname, _args)
          await self._query(q)
          self._executed = q
          return args
docs: Execute stored procedure procname with args
  
          Compatibility warning: PEP-249 specifies that any modified
          parameters must be returned. This is currently impossible
          as they are only available by storing them in a server
          variable and then retrieved by a query. Since stored
          procedures return zero or more result sets, there is no
          reliable way to get at OUT or INOUT parameters via callproc.
          The server variables are named @_procname_n, where procname
          is the parameter above and n is the position of the parameter
          (from zero). Once all result sets generated by the procedure
          have been fetched, you can issue a SELECT @_procname_0, ...
          query using .execute() to get any OUT or INOUT values.
  
          Compatibility warning: The act of calling a stored procedure
          itself creates an empty result set. This appears after any
          result sets generated by the procedure. This is non-standard
          behavior with respect to the DB-API. Be sure to use nextset()
          to advance through all result sets; otherwise you may get
          disconnected.
  
          :param procname: ``str``, name of procedure to execute on server
          :param args: `sequence of parameters to use with procedure
          :returns: the original args.