code: def nan_maximum_filter(arr, ksize):
      '''
      same as scipy.filters.maximum_filter
      but working excluding nans
      '''
      out = np.empty_like(arr)
      _calc(arr, out, ksize//2)
      return ouf nan_maximum_filter(arr, ksize):
      '''
      same as scipy.filters.maximum_filter
      but working excluding nans
      '''
      out = np.empty_like(arr)
      _calc(arr, out, ksize//2)
      return out
docs: same as scipy.filters.maximum_filter
      but working excluding nans