docstr: Retrieve the value at the given coordinates.
  
  Parameters
  ----------
  sid : int
      The asset identifier.
  dt : pd.Timestamp
      The timestamp for the desired data point.
  field : string
      The OHLVC name for the desired data point.
  
  Returns
  -------
  value : float|int
      The value at the given coordinates, ``float`` for OHLC, ``int``
      for 'volume'.
  
  Raises
  ------
  NoDataOnDate
      If the given dt is not a valid market minute (in minute mode) or
      session (in daily mode) according to this reader's tradingcalendar.
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code: def get_value(self, sid, dt, field):
      """
      Retrieve the value at the given coordinates.
  
      Parameters
      ----------
      sid : int
          The asset identifier.
      dt : pd.Timestamp
          The timestamp for the desired data point.
      field : string
          The OHLVC name for the desired data point.
  
      Returns
      -------
      value : float|int
          The value at the given coordinates, ``float`` for OHLC, ``int``
          for 'volume'.
  
      Raises
      ------
      NoDataOnDate
          If the given dt is not a valid market minute (in minute mode) or
          session (in daily mode) according to this reader's tradingcalendar.
      """
      pass
  
file_path: catalyst/catalyst/data/bar_reader.py
imports: from abc import ABCMeta, abstractmethod, abstractproperty
  from six import with_metaclass
label_desc: Use image node_id 6 for calling the BarReader obj's underlying member method code with example usage: obj.get_value(sid, dt, field) without return types