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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 _create(self, postData) : """Creates an index of any type according to postData"""

        if self.infos is None :
            r = self.connection.session.post(self.indexesURL, params = {"collection" : self.collection.name}, data = json.dumps(postData, default=str))
            data = r.json()
            if (r.status_code >= 400) or data['error'] :
                raise CreationError(data['errorMessage'], data)
            self.infos = data