def check_channel_subsystem_request(self, channel, name):
handler_class, larg, kwarg = channel.get_transport()._get_subsystem_handler(name)<EOL>if handler_class is None:<EOL><INDENT>return False<EOL><DEDENT>handler = handler_class(channel, name, self, *larg, **kwarg)<EOL>handler.start()<EOL>return True<EOL>
Determine if a requested subsystem will be provided to the client on
the given channel.  If this method returns C{True}, all future I/O
through this channel will be assumed to be connected to the requested
subsystem.  An example of a subsystem is C{sftp}.

The default implementation checks for a subsystem handler assigned via
L{Transport.set_subsystem_handler}.
If one has been set, the handler is invoked and this method returns
C{True}.  Otherwise it returns C{False}.

@note: Because the default implementation uses the L{Transport} to
    identify valid subsystems, you probably won't need to override this
    method.

@param channel: the L{Channel} the pty request arrived on.
@type channel: L{Channel}
@param name: name of the requested subsystem.
@type name: str
@return: C{True} if this channel is now hooked up to the requested
    subsystem; C{False} if that subsystem can't or won't be provided.
@rtype: bool