code: def _enforce_unique_col_name(
      existing: list[str], new: list[str]
  ) -> list[str]:
      converted_names = []
      unique_names = list(new[:])
      for i, n in enumerate(new):
          if n in existing:
              original_name = n
              fixed_name = n
              duplicate_count = 0
              while fixed_name in existing:
                  fixed_name = n + "_" + str(duplicate_count)
                  duplicate_count += 1
              unique_names[i] = fixed_name
              converted_names.append(
                  f"{original_name}   ->   {fixed_name}"
              )
      if converted_names:
          import warnings
  
          ws = column_name_conflict_doc.format(
              "\n    ".join(converted_names)
          )
          warnings.warn(ws, ColumnNameConflict)
  
      return unique_names
  
file_path: arch/arch/utility/timeseries.py
imports: from __future__ import annotations
  from typing import overload
  import numpy
  import pandas
  from arch.typing import Float64Array, Literal, NDArrayOrFrame
label_desc: Use image node_id 1 for calling a global function with example usage: _enforce_unique_col_name(existing, new) and returns: unique_names