<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add(self, element):
 """ Adds an element to the HyperLogLog. Datatype cardinality will be updated when the object is saved. :param element: the element to add :type element: str """

        if not isinstance(element, six.string_types):
            raise TypeError("Hll elements can only be strings")
        self._adds.add(element)