: When using nested classes, there's no way in Python 2
        to automatically detect that.  Therefore it's possible to set the
        namespace explicitly for a more meaningful ``repr`` output.
    :param bool auto_detect: Instead of setting the *init*, *repr*, *eq*,
        *order*, and *hash* arguments explicitly, assume they are set to
        ``True`` **unless any** of the involved methods for one of the
        arguments is implemented in the *current* class (i.e. it is *not*
        inherited from some base class).

        So for example by implementing ``__eq__`` on a class yourself, *attrs*
        will deduce ``eq=False`` and will create *neither* ``__eq__`` *nor*
        ``__ne__`` (but Python classes come with a sensible ``__ne__`` by
        default, so it *should* be enough to only implement ``__eq__`` in most
        cases).

        .. warning::

           If you prevent *attrs* from creating the ordering methods for you
           (``order=False``, e.g. by implementing ``__le__``), it becomes
           *your* responsibility to make sure its ordering is sound. The best
           way is to use the `functools.total_ordering` decorator.


        Passing ``True`` or ``False`` to *init*, *repr*, *eq*, *order*, *cmp*,
        or *hash* overrides whatever *auto_detect* would determine.

    :param bool repr: Create a ``__repr__`` method with a human readable
        representation of *attrs* attributes..
    :param bool str: Create a ``__str__`` method that is identical to
        ``__repr__``.  This is usually not necessary except for `Exception`\ s.
    :param bool | None eq: If ``True`` or ``None`` (default), add ``__eq__``
        and ``__ne__`` methods that check two instances for equality.

        They compare the instances as if they were tuples of their *attrs*
        attributes if and only if the types of both classes are *identical*!

        .. seealso:: `comparison`
    :param bool | None order: If ``True``, add ``__lt__``, ``__le__``,
        ``__gt__``, and ``__ge__`` methods that behave like *eq* above and
        allow instances to be ordered. If ``None`` (default) mirror value of
        *eq*.

        .. seealso:: `comparison`
    :param bool | None cmp: Setting *cmp* is equivalent to setting *eq* and
        *order* to the same value. Must not be mixed with *eq* or *order*.

        .. seealso:: `comparison`
    :param bool | None unsafe_hash: If ``None`` (default), the ``__hash__``
        method is generated according how *eq* and *frozen* are set.

        1. If *both* are True, *attrs* will generate a ``__hash__`` for you.
        2. If *eq* is True and *frozen* is False, ``__hash__`` will be set to
           None, marking it unhashable (which it is).
        3. If *eq* is False, ``__hash__`` will be left untouched meaning the
           ``__hash__`` method of the base class will be used (if base class is
           ``object``, this means it will fall back to id-based hashing.).

        Although not recommended, you can decide for yourself and force *attrs*
        to create one (e.g. if the class is immutable even though you didn't
        freeze it programmatically) by passing ``True`` or not.  Both of these
        cases are rather special and should be used carefully.

        .. seealso::

           - Our documentation on `hashing`,
           - Python's documentation on `object.__hash__`,
           - and the `GitHub issue that led to the default \
             behavior <https://github.com/python-attrs/attrs/issues/136>`_ for
             more details.

    :param bool | None hash: Alias for *unsafe_hash*. *unsafe_hash* takes
        precedence.
    :param bool init: Create a ``__init__`` method that initializes the *attrs*
        attributes. Leading underscores are stripped for the argument name. If
        a ``__attrs_pre_init__`` method exists on the class, it will be called
        before the class is initialized. If a ``__attrs_post_init__`` method
        exists on the class, it will be called after the class is fully
        initialized.

        If ``init`` is ``False``, an ``__attrs_init__`` method will be injected
        instead. This allows you to define a custom ``__init__`` method that
        can do pre-init work such as ``super().__init__()``, and then call
        ``__attrs_init__()`` and ``__attrs_post_init__()``.

        .. seealso:: `init`
    :param bool slots: Create a :term:`slotted class <slotted classes>` that's
        more memory-efficient. Slotted classes are generally superior to the
        default dict classes, but have some gotchas you should know about, so
        we encourage you to read the :term:`glossary entry <slotted classes>`.
    :param bool frozen: Make instances immutable after initialization.  If
        someone attempts to modify a frozen instance,
        `attrs.exceptions.FrozenInstanceError` is raised.

        .. note::

            1. This is achieved by installing a custom ``__setattr__`` method
               on your class, so you can't implement your own.

            2. True immutability is impossible in Python.

            3. This *does* have a minor a runtime performance `impact
               <how-frozen>` when initializing new instances.  In other words:
               ``__init__`` is slightly slower with ``frozen=True``.

            4. If a class is frozen, you cannot modify ``self`` in
               ``__attrs_post_init__`` or a self-written ``__init__``. You can
               circumvent that limitation by using ``object.__setattr__(self,
               "attribute_name", value)``.

            5. Subclasses of a frozen class are frozen too.

    :param bool weakref_slot: Make instances weak-referenceable.  This has no
        effect unless ``slots`` is also enabled.
    :param bool auto_attribs: If ``True``, collect :pep:`526`-annotated
        attributes from the class body.

        In this case, you **must** annotate every field.  If *attrs* encounters
        a field that is set to an `attr.ib` but lacks a type annotation, an
        `attr.exceptions.UnannotatedAttributeError` is raised.  Use
        ``field_name: typing.Any = attr.ib(...)`` if you don't want to set a
        type.

        If you assign a value to those attributes (e.g. ``x: int = 42``), that
        value becomes the default value like if it were passed using
        ``attr.ib(default=42)``.  Passing an instance of `attrs.Factory` also
        works as expected in most cases (see warning below).

        Attributes annotated as `typing.ClassVar`, and attributes that are
        neither annotated nor set to an `attr.ib` are **ignored**.

        .. warning::
           For features that use the attribute name to create decorators (e.g.
           :ref:`validators <validators>`), you still *must* assign `attr.ib`
           to them. Otherwise Python will either not find the name or try to
           use the default value to call e.g. ``validator`` on it.

           These errors can be quite confusing and probably the most common bug
           report on our bug tracker.

    :param bool kw_only: Make all attributes keyword-only in the generated
        ``__init__`` (if ``init`` is ``False``, this parameter is ignored).
    :param bool cache_hash: Ensure that the object's hash code is computed only
        once and stored on the object.  If this is set to ``True``, hashing
        must be either explicitly or implicitly enabled for this class.  If the
        hash code is cached, avoid any reassignments of fields involved in hash
        code computation or mutations of the objects those fields point to
        after object creation.  If such changes occur, the behavior of the
        object's hash code is undefined.
    :param bool auto_exc: If the class subclasses `BaseException` (which
        implicitly includes any subclass of any exception), the following
        happens to behave like a well-behaved Python exceptions class:

        - the values for *eq*, *order*, and *hash* are ignored and the
          instances compare and hash by the instance's ids (N.B. *attrs* will
          *not* remove existing implementations of ``__hash__`` or the equality
          methods. It just won't add own ones.),
        - all attributes that are either passed into ``__init__`` or have a
          default value are additionally available as a tuple in the ``args``
          attribute,
        - the value of *str* is ignored leaving ``__str__`` to base classes.
    :param bool collect_by_mro: Setting this to `True` fixes the way *attrs*
       collects attributes from base classes.  The default behavior is
       incorrect in certain cases of multiple inheritance.  It should be on by
       default but is kept off for backward-compatibility.

       .. seealso::
          Issue `#428 <https://github.com/python-attrs/attrs/issues/428>`_

    :param bool | None getstate_setstate:
       .. note::
          This is usually only interesting for slotted classes and you should
          probably just set *auto_detect* to `True`.

       If `True`, ``__getstate__`` and ``__setstate__`` are generated and
       attached to the class. This is necessary for slotted classes to be
       pickleable. If left `None`, it's `True` by default for slotted classes
       and ``False`` for dict classes.

       If *auto_detect* is `True`, and *getstate_setstate* is left `None`, and
       **either** ``__getstate__`` or ``__setstate__`` is detected directly on
       the class (i.e. not inherited), it is set to `False` (this is usually
       what you want).

    :param on_setattr: A callable that is run whenever the user attempts to set
        an attribute (either by assignment like ``i.x = 42`` or by using
        `setattr` like ``setattr(i, "x", 42)``). It receives the same arguments
        as validators: the instance, the attribute that is being modified, and
        the new value.

        If no exception is raised, the attribute is set to the return value of
        the callable.

        If a list of callables is passed, they're automatically wrapped in an
        `attrs.setters.pipe`.
    :type on_setattr: `callable`, or a list of callables, or `None`, or
        `attrs.setters.NO_OP`

    :param callable | None field_transformer:
        A function that is called with the original class object and all fields
        right before *attrs* finalizes the class.  You can use this, e.g., to
        automatically add converters or validators to fields based on their
        types.

        .. seealso:: `transform-fields`

    :param bool match_args:
        If `True` (default), set ``__match_args__`` on the class to support
        :pep:`634` (Structural Pattern Matching). It is a tuple of all
        non-keyword-only ``__init__`` parameter names on Python 3.10 and later.
        Ignored on older Python versions.

    .. versionadded:: 16.0.0 *slots*
    .. versionadded:: 16.1.0 *frozen*
    .. versionadded:: 16.3.0 *str*
    .. versionadded:: 16.3.0 Support for ``__attrs_post_init__``.
    .. versionchanged:: 17.1.0
       *hash* supports ``None`` as value which is also the default now.
    .. versionadded:: 17.3.0 *auto_attribs*
    .. versionchanged:: 18.1.0
       If *these* is passed, no attributes are deleted from the class body.
    .. versionchanged:: 18.1.0 If *these* is ordered, the order is retained.
    .. versionadded:: 18.2.0 *weakref_slot*
    .. deprecated:: 18.2.0
       ``__lt__``, ``__le__``, ``__gt__``, and ``__ge__`` now raise a
       `DeprecationWarning` if the classes compared are subclasses of
       each other. ``__eq`` and ``__ne__`` never tried to compared subclasses
       to each other.
    .. versionchanged:: 19.2.0
       ``__lt__``, ``__le__``, ``__gt__``, and ``__ge__`` now do not consider
       subclasses comparable anymore.
    .. versionadded:: 18.2.0 *kw_only*
    .. versionadded:: 18.2.0 *cache_hash*
    .. versionadded:: 19.1.0 *auto_exc*
    .. deprecated:: 19.2.0 *cmp* Removal on or after 2021-06-01.
    .. versionadded:: 19.2.0 *eq* and *order*
    .. versionadded:: 20.1.0 *auto_detect*
    .. versionadded:: 20.1.0 *collect_by_mro*
    .. versionadded:: 20.1.0 *getstate_setstate*
    .. versionadded:: 20.1.0 *on_setattr*
    .. versionadded:: 20.3.0 *field_transformer*
    .. versionchanged:: 21.1.0
       ``init=False`` injects ``__attrs_init__``
    .. versionchanged:: 21.1.0 Support for ``__attrs_pre_init__``
    .. versionchanged:: 21.1.0 *cmp* undeprecated
    .. versionadded:: 21.3.0 *match_args*
    .. versionadded:: 22.2.0
       *unsafe_hash* as an alias for *hash* (for :pep:`681` compliance).
    Nc