in clearbox/features.py [0:0]
def evaluate(self, signal_data: pd.DataFrame) -> npt.NDArray[float]:
"""Evaluate the node on `signal_data`.
Args:
signal_data: `pd.DataFrame` of signal values.
Returns:
Array of results as floats.
"""
return np.sum(
np.stack([arg.evaluate(signal_data) for arg in self._args], axis=0),
axis=0,
)