code: def nvi(
      close, volume, length=None, initial=None, offset=None, **kwargs
  ):
      """Indicator: Negative Volume Index (NVI)"""
      # Validate arguments
      length = int(length) if length and length > 0 else 1
      # min_periods = int(kwargs["min_periods"]) if "min_periods" in kwargs and kwargs["min_periods"] is not None else length
      initial = int(initial) if initial and initial > 0 else 1000
      close = verify_series(close, length)
      volume = verify_series(volume, length)
      offset = get_offset(offset)
  
      if close is None or volume is None:
          return
  
      # Calculate Result
      roc_ = roc(close=close, length=length)
      signed_volume = signed_series(volume, 1)
      nvi = signed_volume[signed_volume < 0].abs() * roc_
      nvi.fillna(0, inplace=True)
      nvi.iloc[0] = initial
      nvi = nvi.cumsum()
  
      # Offset
      if offset != 0:
          nvi = nvi.shift(offset)
  
      # Handle fills
      if "fillna" in kwargs:
          nvi.fillna(kwargs["fillna"], inplace=True)
      if "fill_method" in kwargs:
          nvi.fillna(method=kwargs["fill_method"], inplace=True)
  
      # Name and Categorize it
      nvi.name = f"NVI_{length}"
      nvi.category = "volume"
  
      return nvi
  
label_desc: Use image node_id 1 for calling a global function with example usage: nvi(close, volume, length, initial, offset) and returns: nvi