def add(self, value, time=None):
''' Add the value to the set.
:param value: The value to add to the set
:param time: The time to add this value at
'''
time = time or current_time()
self.pdata[value] = time
def set(self, value, time=None):
''' Given a new value, attempt to set it in the register
:param value: The new value to set
:param time: The new time to compare with
'''
self.time = time or current_time()
self.data = value
def remove(self, value, time=None):
''' Remove the value from the set.
:param value: The value to remove from the set
:param time: The time to remove this value at
'''
assert value in self.pdata, "cannot remove a value that is not present"
time = time or current_time()
self.ndata[value] = time
