docs: def map_val(dest, src, key, default=None, src_key=None):
      """Will ensure a dict has values sourced from either
          another dict or based on the provided default"""
      if not src_key:
          src_key = key
  
      if src_key in src:
          dest[key] = src[src_key]
      else:
          if default is not None:
              dest[key] = default