def block_offset_timeout(
raiden: RaidenService,
error_message: Optional[str] = None,
offset: Optional[BlockOffset] = None,
safety_margin: int = 5,
) -> BlockTimeout:
"""
Returns a BlockTimeout that will fire after a number of blocks. Usually created
at the same time as a set of transfers to wait until their expiration.
"""
expiration = BlockNumber(raiden.get_block_number() +
(offset or raiden.config.settle_timeout) +
safety_margin)
exception = RuntimeError(
error_message
or "Events were not completed in the required number of blocks.")
return BlockTimeout(
raiden=raiden,
exception_to_throw=exception,
block_number=expiration,
retry_timeout=DEFAULT_RETRY_TIMEOUT,
)
