code: def _to_dict_fixed_width_arrays(self, var_len_str=True):
          
          self.strings_to_categoricals()
          obs_rec, uns_obs = df_to_records_fixed_width(self._obs, var_len_str)
          var_rec, uns_var = df_to_records_fixed_width(self._var, var_len_str)
          layers = self.layers.as_dict()
          d = {
              'X': self._X,
              'obs': obs_rec,
              'var': var_rec,
              'obsm': self._obsm,
              'varm': self._varm,
              'layers': layers,
              # add the categories to the unstructured annotation
              'uns': {**self._uns, **uns_obs, **uns_var}}
  
          if self.raw is not None:
              self.strings_to_categoricals(self.raw._var)
              var_rec, uns_var = df_to_records_fixed_width(self.raw._var, var_len_str)
              d['raw.X'] = self.raw.X
              d['raw.var'] = var_rec
              d['raw.varm'] = self.raw.varm
              d['raw.cat'] = uns_var
  
          return d
docs: A dict of arrays that stores data and annotation.
  
          It is sufficient for reconstructing the object.