class_docstr: Provide attribute-style access to configuration dict.
class_docstr_tok: ["Provide","attribute-style","access","to","configuration","dict","."]
code: def __setattr__(self, key, value):
      # you can't set new keys
      if key in self._config:
          option = self._options[key]
          if option.validator:
              option.validator(value)
          self._config[key] = value
          if option.callback:
              option.callback(key, value)
      else:
          msg = "You can only set the value of existing options"
          raise AttributeError(msg)
  
file_path: geopandas/geopandas/_config.py
imports: from collections import namedtuple
  import textwrap
label_desc: Use image node_id 2 for calling the Options obj's underlying member method code with example usage: obj.__setattr__(key, value) without return types