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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def remove_accessibility_type(self, accessibility_type=None):
 """Removes an accessibility type. :param accessibility_type: accessibility type to remove :type accessibility_type: ``osid.type.Type`` :raise: ``NoAccess`` -- ``Metadata.isReadOnly()`` is ``true`` :raise: ``NotFound`` -- acessibility type not found :raise: ``NullArgument`` -- ``accessibility_type`` is ``null`` *compliance: mandatory -- This method must be implemented.* """

        if accessibility_type is None:
            raise NullArgument
        metadata = Metadata(**settings.METADATA['accessibility_type'])
        if metadata.is_read_only() or metadata.is_required():
            raise NoAccess()
        if (accessibility_type._my_map['id']) not in self._my_map['accessibility_type']:
            raise NotFound()
        self._my_map['accessibility_types'].remove(accessibility_type._my_map['id'])