code: def was_active(reference_date_value, asset):
      
      return (
          asset.start_date.value
          <= reference_date_value
          <= asset.end_date.value
      )
docs: Whether or not `asset` was active at the time corresponding to
      `reference_date_value`.
  
      Parameters
      ----------
      reference_date_value : int
          Date, represented as nanoseconds since EPOCH, for which we want to know
          if `asset` was alive.  This is generally the result of accessing the
          `value` attribute of a pandas Timestamp.
      asset : Asset
          The asset object to check.
  
      Returns
      -------
      was_active : bool
          Whether or not the `asset` existed at the specified time.