docs: def pexpect(self):
          """
          Run command and return pexpect process object.
  
          NOTE: Requires you to pip install 'pexpect' or will fail.
          """
          import pexpect
  
          assert not self._ignore_errors
  
          _check_directory(self.directory)
  
          arguments = self.arguments
  
          return pexpect.spawn(
              arguments[0], args=arguments[1:], env=self.env, cwd=self.directory
          )