cirq.DURATION_LIKE

This symbol is a type alias.

A cirq.Duration or value that can trivially converted to one.

Source:

DURATION_LIKE = Union[
    NoneType,
    datetime.timedelta,
    ForwardRef('cirq.Duration')
]

A datetime.timedelta is a cirq.DURATION_LIKE. It is converted while preserving its duration.

None is a cirq.DURATION_LIKE that converts into a zero-length duration.

Note that 0 is a DURATION_LIKE, despite the fact that int is not listed, because 0 is the only integer where the physical unit doesn't matter.