* Numbers are compared arithmetically.

+* The values :const:`float('NaN')` and :const:`Decimal('NaN')` are special.

+ The are identical to themselves, ``x is x`` but are not equal to themselves,

+ ``x != x``. Additionally, comparing any value to a not-a-number value

+ will return ``False``. For example, both ``3 < float('NaN')`` and

+ ``float('NaN') < 3`` will return ``False``.

* Bytes objects are compared lexicographically using the numeric values of their

value)`` lists compare equal. [#]_ Outcomes other than equality are resolved

consistently, but are not otherwise defined. [#]_

+* Sets and frozensets define comparison operators to mean subset and superset

+ tests. Those relations do not define total orderings (the two sets ``{1,2}``

+ and {2,3} are not equal, nor subsets of one another, nor supersets of one

+ another). Accordingly, sets are not appropriate arguments for functions

+ which depend on total ordering. For example, :func:`min`, :func:`max`, and

+ :func:`sorted` produce undefined results given a list of sets as inputs.

* Most other objects of builtin types compare unequal unless they are the same

object; the choice whether one object is considered smaller or larger than

another one is made arbitrarily but consistently within one execution of a

+Comparison of objects of the differing types depends on whether either

+of the types provide explicit support for the comparison. Most numberic types

+can be compared with one another, but comparisons of :class:`float` and

+:class:`Decimal` are not supported to avoid the inevitable confusion arising

+from representation issues such as ``float('1.1')`` being inexactly represented

+and therefore not exactly equal to ``Decimal('1.1')`` which is. When

+cross-type comparison is not supported, the comparison method returns

+``NotImplemented``. This can create the illusion of non-transitivity between

+supported cross-type comparisons and unsupported comparisons. For example,

+``Decimal(2) == 2`` and `2 == float(2)`` but ``Decimal(2) != float(2)``.

The operators :keyword:`in` and :keyword:`not in` test for membership. ``x in

s`` evaluates to true if *x* is a member of *s*, and false otherwise. ``x not

in s`` returns the negation of ``x in s``. All built-in sequences and set types

support this as well as dictionary, for which :keyword:`in` tests whether a the

-dictionary has a given key.

-For the list and tuple types, ``x in y`` is true if and only if there exists an

-index *i* such that ``x == y[i]`` is true.

+dictionary has a given key. For container types such as list, tuple, set,

+frozenset, dict, or collections.deque, the expression ``x in y`` equivalent to

+``any(x is e or x == e for val e in y)``.

For the string and bytes types, ``x in y`` is true if and only if *x* is a

substring of *y*. An equivalent test is ``y.find(x) != -1``. Empty strings are