class_docstr: On-balance volume (OBV)
  
  It relates price and volume in the stock market. OBV is based on a
  cumulative total volume.
  
  https://en.wikipedia.org/wiki/On-balance_volume
  
  Args:
      close(pandas.Series): dataset 'Close' column.
      volume(pandas.Series): dataset 'Volume' column.
      fillna(bool): if True, fill nan values.
docstr: On-balance volume (OBV)
  
  Returns:
      pandas.Series: New feature generated.
docstr_tok: ["On-balance","volume","(","OBV",")","Returns",":","pandas.Series",":","New","feature","generated","."]
code: def on_balance_volume(self) -> pd.Series:
      """On-balance volume (OBV)
  
      Returns:
          pandas.Series: New feature generated.
      """
      obv = self._check_fillna(self._obv, value=0)
      return pd.Series(obv, name="obv")
  
imports: import typing
  import numpy
  import pandas
  from ta.utils import IndicatorMixin, _ema
label_desc: Use image node_id 3 for calling the OnBalanceVolumeIndicator obj's underlying member method code with example usage: obj.on_balance_volume() and returns: pd