docs: def fbool(value):
      """boolean"""
      if isinstance(value, str_types):
          value = value.lower()
          if value == "false":
              value = False
          elif value == "true":
              value = True
          elif value:
              value = bool(float(value))
          else:
              raise ValueError("empty string")
      else:
          value = bool(float(value))
      return value