docs: def _invoke(self, *params):
  		"""
  		Invoke self.exe as a subprocess
  		"""
  		cmd = [self.exe] + list(params)
  		proc = subprocess.Popen(
  			cmd, stdout=subprocess.PIPE,
  			stderr=subprocess.PIPE, cwd=self.location, env=self.env)
  		stdout, stderr = proc.communicate()
  		if not proc.returncode == 0:
  			raise RuntimeError(stderr.strip() or stdout.strip())
  		return stdout.decode('utf-8')