docs: async def run_script(self, script):
          """Execute the script and save results."""
          # Create a Bash command to add all the tools to PATH.
          tools_paths = ':'.join([map_["dest"] for map_ in self.tools_volumes])
          add_tools_path = 'export PATH=$PATH:{}'.format(tools_paths)
          # Spawn another child bash, to avoid running anything as PID 1, which has special
          # signal handling (e.g., cannot be SIGKILL-ed from inside).
          # A login Bash shell is needed to source /etc/profile.
          bash_line = '/bin/bash --login; exit $?' + os.linesep
          script = os.linesep.join(['set -x', 'set +B', add_tools_path, script]) + os.linesep
          self.proc.stdin.write(bash_line.encode('utf-8'))
          await self.proc.stdin.drain()
          self.proc.stdin.write(script.encode('utf-8'))
          await self.proc.stdin.drain()
          self.proc.stdin.close()