Values
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Values objects returned by TreeMap's methods are views on the calling TreeMap instance. Values objects supports these methods:

``remove(o)`` removes the first entry with the value o from the underlying TreeMap instance.

``clear()`` clears the underlying TreeMap instance.

``to_list()`` returns a Python list of all the values in the underlying TreeMap.

Set can be represented using strings (``print()`` or ``str()``), iterated (``iter()``), and checked for membership (``element in self``).