code: def _check_install(self):
          
          try:
              subprocess.check_output(['which', 'tlgu'])
          except Exception as exc:
              logger.info('TLGU not installed: %s', exc)
              logger.info('Installing TLGU.')
              if not subprocess.check_output(['which', 'gcc']):
                  logger.error('GCC seems not to be installed.')
              else:
                  tlgu_path_rel = '~/cltk_data/greek/software/greek_software_tlgu'
                  tlgu_path = os.path.expanduser(tlgu_path_rel)
                  if not self.testing:
                      print('Do you want to install TLGU?')
                      print('To continue, press Return. To exit, Control-C.')
                      input()
                  else:
                      print('Automated or test build, skipping keyboard input confirmation for installation of TLGU.')
                  try:
                      command = 'cd {0} && make install'.format(tlgu_path)
                      print('Going to run command:', command)
                      p_out = subprocess.call(command, shell=True)
                      if p_out == 0:
                          logger.info('TLGU installed.')
                      else:
                          logger.error('TLGU install without sudo failed.')
                  except Exception as exc:
                      logger.error('TLGU install failed: %s', exc)
                  else:  # for Linux needing root access to '/usr/local/bin'
                      if not self.testing:
                          print('Could not install without root access. Do you want to install TLGU with sudo?')
                          command = 'cd {0} && sudo make install'.format(tlgu_path)
                          print('Going to run command:', command)
                          print('To continue, press Return. To exit, Control-C.')
                          input()
                          p_out = subprocess.call(command, shell=True)
                      else:
                          command = 'cd {0} && sudo make install'.format(tlgu_path)
                          p_out = subprocess.call(command, shell=True)
                      if p_out == 0:
                          logger.info('TLGU installed.')
                      else:
                          logger.error('TLGU install with sudo failed.')
docs: Check if tlgu installed, if not install it.