code: def createCategoryFilter(self, filterName, positiveExamples, negativeExamples=[]):
          
          samples = {"positiveExamples": [{"text": s} for s in positiveExamples],
                     "negativeExamples": [{"text": s} for s in negativeExamples]}
          body = json.dumps(samples)
          return self._classify.createCategoryFilter(self._retina, filterName, body)
docs: Get a classifier filter (fingerprint) for positive and negative text samples
          Args:
              filterName, str: A unique name for the filter. (required)
              positiveExamples, list(str): The list of positive example texts. (required)
              negativeExamples, list(str): The list of negative example texts. (optional)
          Returns:
              CategoryFilter
          Raises:
              CorticalioException: if the request was not successful