docs: def _call_cli(self, command, cwd=None, universal_newlines=False, redirect_stderr=False):
  		"""
  		Executes the given command, internally using Popen. The output of
  		stdout and stderr are returned as a tuple. The returned tuple looks
  		like: (stdout, stderr, returncode)
  
  		Parameters
  		----------
  		command: string
  			The command to execute.
  		cwd: string
  			Change the working directory of the program to the specified path.
  		universal_newlines: boolean
  			Enable the universal_newlines feature of Popen.
  		redirect_stderr: boolean
  			If True, redirect stderr into stdout
  		"""
  		command = str(command.encode("utf-8").decode("ascii", "ignore"))
  		env = os.environ.copy()
  		env.update(self.envvars)
  		stderr = STDOUT if redirect_stderr else PIPE
  		proc = Popen(shlex.split(command), stdout=PIPE, stderr=stderr, cwd=cwd, universal_newlines=universal_newlines, env=env)
  		stdout, stderr = proc.communicate()
  
  		return (stdout, stderr, proc.returncode)