def __init__(self, command_line):
<EOL>from subprocess import Popen, PIPE<EOL>self.cmd = shlsplit(command_line)<EOL>self.process = Popen(<EOL>self.cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE, bufsize=<NUM_LIT:0><EOL>)<EOL>self.timeout = None<EOL>
Create a new CommandProxy instance. The instance created by this
class can be passed as an argument to the `.Transport` class.

:param str command_line:
    the command that should be executed and used as the proxy.