'Remove a single timestamp.
Arguments:
timestamp  -- timestamp (in ISO format) of the item to remove.'

def del_timestamp(self, timestamp):

    if (timestamp in self._timestamps):
        timestamps = [i for i in self.iterables if isinstance(i, Timestamp)]
        for ts in timestamps:
            if (ts['value'] == timestamp):
                self.xml.remove(ts.xml)
                self.iterables.remove(ts)
                return True
    return False
