Fix making get_level_lengths non-private

Author: jnothman

pandas/formats/excel.py

@@ -528,7 +528,7 @@ def _format_hierarchical_rows(self):
                 # Format hierarchical rows as merged cells.
                 level_strs = self.df.index.format(sparsify=True, adjoin=False,
                                                   names=False)
-                level_lengths = _get_level_lengths(level_strs)
+                level_lengths = get_level_lengths(level_strs)
 
                 for spans, levels, labels in zip(level_lengths,
                                                  self.df.index.levels,

pandas/formats/format.py

@@ -1355,7 +1355,7 @@ def _write_hierarchical_rows(self, fmt_values, indent):
             levels = frame.index.format(sparsify=sentinel, adjoin=False,
                                         names=False)
 
-            level_lengths = _get_level_lengths(levels, sentinel)
+            level_lengths = get_level_lengths(levels, sentinel)
             inner_lvl = len(level_lengths) - 1
             if truncate_v:
                 # Insert ... row and adjust idx_values and