code: def to_lower(ctx, param, value):
      """Click callback, converts values to lowercase."""
      return value.lower()
  
file_path: rasterio/rasterio/rio/helpers.py
imports: import json
  import os
  import click
  from rasterio.errors import FileOverwriteError
label_desc: Use image node_id 4 for calling a global function with example usage: to_lower(ctx, param, value) and returns: value