docs: def horizontal_padding(self, padding=None):
          """Returns or sets (if a value is provided) the chart's horizontal
          padding. This determines how much space will be on either side of the
          display area, as a proportion of overall width, and should be a value
          between 0 and 0.5
  
          :param float padding: If given, the chart's horizontal_padding\
          will be set to this.
          :raises ValueError: if a value outside of 0 < n < 0.5 is given.
          :rtype: float"""
  
          if padding is None:
              return self._horizontal_padding
          else:
              if not isinstance(padding, float):
                  raise TypeError("padding must be float, not '%s'" % str(padding))
              if not 0 < padding < 0.5:
                  raise ValueError(
                   "padding must be between 0 and 0.5 (not inclusive), not '%s'" % str(padding)
                  )
              self._horizontal_padding = padding