in processor.py [0:0]
def __add__(self, other: Self | PartProcessor) -> _ChainProcessor:
"""Adds `other` to this processor: self + other.
Args:
other: a processor to add to `self`.
Returns:
The chain of this process with `other`.
"""
if isinstance(other, PartProcessor):
return _ChainProcessor([self.call, other.to_processor().call])
elif isinstance(other, _ChainProcessor):
return _ChainProcessor([self.call] + other._processor_list)
else:
other: Processor = other # Make pytype happy.
return _ChainProcessor([self.call, other.call])