code: def multiply_volume(clip, factor, start_time=None, end_time=None):
      """Returns a clip with audio volume multiplied by the
      value `factor`. Can be applied to both audio and video clips.
  
      Parameters
      ----------
  
      factor : float
        Volume multiplication factor.
  
      start_time : float, optional
        Time from the beginning of the clip until the volume transformation
        begins to take effect, in seconds. By default at the beginning.
  
      end_time : float, optional
        Time from the beginning of the clip until the volume transformation
        ends to take effect, in seconds. By default at the end.
  
      Examples
      --------
  
      >>> from moviepy import AudioFileClip
      >>>
      >>> music = AudioFileClip('music.ogg')
      >>> doubled_audio_clip = clip.multiply_volume(2)  # doubles audio volume
      >>> half_audio_clip = clip.multiply_volume(0.5)  # half audio
      >>>
      >>> # silenced clip during one second at third
      >>> silenced_clip = clip.multiply_volume(0, start_time=2, end_time=3)
      """
      if start_time is None and end_time is None:
          return clip.transform(
              lambda get_frame, t: factor * get_frame(t),
              keep_duration=True,
          )
  
      return clip.transform(
          _multiply_volume_in_range(
              factor,
              clip.start if start_time is None else start_time,
              clip.end if end_time is None else end_time,
              clip.nchannels,
          ),
          keep_duration=True,
      )
  
imports: import numpy
  from moviepy.decorators import audio_video_fx, convert_parameter_to_seconds
label_desc: Use image node_id 2 for calling a global function with example usage: multiply_volume(clip, factor, start_time, end_time) and returns: clip, clip