code: def eri(high, low, close, length=None, offset=None, **kwargs):
      """Indicator: Elder Ray Index (ERI)"""
      # Validate arguments
      length = int(length) if length and length > 0 else 13
      high = verify_series(high, length)
      low = verify_series(low, length)
      close = verify_series(close, length)
      offset = get_offset(offset)
  
      if high is None or low is None or close is None:
          return
  
      # Calculate Result
      ema_ = ema(close, length)
      bull = high - ema_
      bear = low - ema_
  
      # Offset
      if offset != 0:
          bull = bull.shift(offset)
          bear = bear.shift(offset)
  
      # Handle fills
      if "fillna" in kwargs:
          bull.fillna(kwargs["fillna"], inplace=True)
          bear.fillna(kwargs["fillna"], inplace=True)
      if "fill_method" in kwargs:
          bull.fillna(method=kwargs["fill_method"], inplace=True)
          bear.fillna(method=kwargs["fill_method"], inplace=True)
  
      # Name and Categorize it
      bull.name = f"BULLP_{length}"
      bear.name = f"BEARP_{length}"
      bull.category = bear.category = "momentum"
  
      # Prepare DataFrame to return
      data = {bull.name: bull, bear.name: bear}
      df = DataFrame(data)
      df.name = f"ERI_{length}"
      df.category = bull.category
  
      return df
  
label_desc: Use image node_id 1 for calling a global function with example usage: eri(high, low, close, length, offset) and returns: df