docs: def default(self, obj):
          """If input object is an ndarray it will be converted into a dict
          holding dtype, shape and the data, base64 encoded and blosc compressed.
          """
          if isinstance(obj, np.ndarray):
              if obj.flags['C_CONTIGUOUS']:
                  obj_data = obj.data
              else:
                  cont_obj = np.ascontiguousarray(obj)
                  assert(cont_obj.flags['C_CONTIGUOUS'])
                  obj_data = cont_obj.data
              if has_blosc:
                  obj_data = blosc.compress(obj_data, typesize=8)
              data_b64 = base64.b64encode(obj_data)
              # http://stackoverflow.com/questions/24369666/typeerror-b1-is-not-json-serializable
              if sys.version_info >= (3, 0):
                  data_b64 = data_b64.decode('utf-8')
              return dict(__ndarray__=data_b64,
                          dtype=str(obj.dtype),
                          shape=obj.shape)
          return json.JSONEncoder.default(self, obj)