def set_combine_stderr(self, combine):
data = '<STR_LIT>'<EOL>self.lock.acquire()<EOL>try:<EOL><INDENT>old = self.combine_stderr<EOL>self.combine_stderr = combine<EOL>if combine and not old:<EOL><INDENT>data = self.in_stderr_buffer.empty()<EOL><DEDENT><DEDENT>finally:<EOL><INDENT>self.lock.release()<EOL><DEDENT>if len(data) > <NUM_LIT:0>:<EOL><INDENT>self._feed(data)<EOL><DEDENT>return old<EOL>
Set whether stderr should be combined into stdout on this channel.
The default is C{False}, but in some cases it may be convenient to
have both streams combined.

If this is C{False}, and L{exec_command} is called (or C{invoke_shell}
with no pty), output to stderr will not show up through the L{recv}
and L{recv_ready} calls.  You will have to use L{recv_stderr} and
L{recv_stderr_ready} to get stderr output.

If this is C{True}, data will never show up via L{recv_stderr} or
L{recv_stderr_ready}.

@param combine: C{True} if stderr output should be combined into
    stdout on this channel.
@type combine: bool
@return: previous setting.
@rtype: bool

@since: 1.1