code: def compute_sizes(sizes, size_fn, scaling_factor, scaling_method, base_size):
      
      if sizes.dtype.kind not in ('i', 'f'):
          return None
      if scaling_method == 'area':
          pass
      elif scaling_method == 'width':
          scaling_factor = scaling_factor**2
      else:
          raise ValueError(
              'Invalid value for argument "scaling_method": "{}". '
              'Valid values are: "width", "area".'.format(scaling_method))
      sizes = size_fn(sizes)
      return (base_size*scaling_factor*sizes)
docs: Scales point sizes according to a scaling factor,
      base size and size_fn, which will be applied before
      scaling.