quoracle\expr.py

"""
Original code available at: https://github.com/mwhittaker/quoracle
"""
class Node(Expr[T]):
    def __init__(self,
                 x: T,
                 capacity: Optional[float] = None,
                 read_capacity: Optional[float] = None,
                 write_capacity: Optional[float] = None,
                 latency: datetime.timedelta = None) -> None:
        self.x = x

        # A user either specifies capacity or (read_capacity and
        # write_capacity), but not both.
        if (capacity is None and
                read_capacity is None and
                write_capacity is None):
            self.read_capacity = 1.0
            self.write_capacity = 1.0
        elif (capacity is not None and
              read_capacity is None and
              write_capacity is None):
            self.read_capacity = capacity
            self.write_capacity = capacity
        elif (capacity is None and
              read_capacity is not None and
              write_capacity is not None):
            self.read_capacity = read_capacity
            self.write_capacity = write_capacity
        else:
            raise ValueError('You must specify capacity or (read_capacity '
                             'and write_capacity)')

        if latency is None:
            self.latency = datetime.timedelta(seconds=1)
        else:
            self.latency = latency