@utilities.arguments_not_none<EOL><INDENT>def add_accessibility_type(self, accessibility_type):<DEDENT>
raise errors.Unimplemented()<EOL>
Adds an accessibility type.

        Multiple types can be added.

        arg:    accessibility_type (osid.type.Type): a new accessibility
                type
        raise:  InvalidArgument - ``accessibility_type`` is invalid
        raise:  NoAccess - ``Metadata.isReadOnly()`` is ``true``
        raise:  NullArgument - ``accessibility_t_ype`` is ``null``
        *compliance: mandatory -- This method must be implemented.*