code: def ranges(self):
          
          bucket_fns = {
              'boolean': linear_buckets,
              'flag': linear_buckets,
              'count': linear_buckets,
              'enumerated': linear_buckets,
              'categorical': linear_buckets,
              'linear': linear_buckets,
              'exponential': exponential_buckets,
          }
  
          if self._kind not in bucket_fns:
              raise ParserError('Unknown kind "%s" for histogram "%s".' % (self._kind, self._name))
  
          fn = bucket_fns[self._kind]
          return fn(self.low(), self.high(), self.n_buckets())
docs: Return an array of lower bounds for each bucket in the histogram.