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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 defaultannotator(self, annotationtype, set=None):
 """Obtain the default annotator for the specified annotation type and set. Arguments: annotationtype: The type of annotation, this is conveyed by passing the corresponding annototion class (such as :class:`PosAnnotation` for example), or a member of :class:`AnnotationType`, such as ``AnnotationType.POS``. set (str):
 the set, should formally be a URL pointing to the set definition Returns: the set (str) Raises: :class:`NoDefaultError` if the annotation type does not exist or if there is ambiguity (multiple sets for the same type) """


        if inspect.isclass(annotationtype) or isinstance(annotationtype,AbstractElement): annotationtype = annotationtype.ANNOTATIONTYPE
        if not set: set = self.defaultset(annotationtype)
        try:
            return self.annotationdefaults[annotationtype][set]['annotator']
        except KeyError:
            raise NoDefaultError