'Whether or not this term represents a trailing window computation.
If term.windowed is truthy, its compute_from_windows method will be
called with instances of AdjustedArray as inputs.
If term.windowed is falsey, its compute_from_baseline will be called
with instances of np.ndarray as inputs.'

@lazyval
def windowed(self):

    return ((self.window_length is not NotSpecified) and (self.window_length > 0))
