':class:`Attribute` specifies constraints for attributes of objects which
derive from playbook data.  The attributes of the object are basically
a schema for the yaml playbook.
:kwarg isa: The type of the attribute.  Allowable values are a string
representation of any yaml basic datatype, python class, or percent.
(Enforced at post-validation time).
:kwarg private: (not used)
:kwarg default: Default value if unspecified in the YAML document.
:kwarg required: Whether or not the YAML document must contain this field.
If the attribute is None when post-validated, an error will be raised.
:kwarg listof: If isa is set to "list", this can optionally be set to
ensure that all elements in the list are of the given type. Valid
values here are the same as those for isa.
:kwarg priority: The order in which the fields should be parsed. Generally
this does not need to be set, it is for rare situations where another
field depends on the fact that another field was parsed first.
:kwarg class_type: If isa is set to "class", this can be optionally set to
a class (not a string name). The YAML data for this field will be
passed to the __init__ method of that class during post validation and
the field will be an instance of that class.
:kwarg always_post_validate: Controls whether a field should be post
validated or not (default: True).
:kwarg inherit: A boolean value, which controls whether the object
containing this field should attempt to inherit the value from its
parent object if the local value is None.'

def __init__(self, isa=None, private=False, default=None, required=False, listof=None, priority=0, class_type=None, always_post_validate=False, inherit=True):

    self.isa = isa
    self.private = private
    self.default = default
    self.required = required
    self.listof = listof
    self.priority = priority
    self.class_type = class_type
    self.always_post_validate = always_post_validate
    self.inherit = inherit
    if ((default is not None) and (self.isa in ('list', 'dict', 'set'))):
        self.default = deepcopy(default)
    else:
        self.default = default
