original_string: public function configKey($keyname, $option = null, $value = null)
      {
          if ($option === null) {
              $default = $this->_config;
              $local = isset($this->_keyConfig[$keyname]) ? $this->_keyConfig[$keyname] : [];
  
              return $local + $default;
          }
          if (!is_array($option)) {
              $option = [$option => $value];
          }
          $this->_keyConfig[$keyname] = $option;
  
          return null;
      }
code: public function configKey($keyname, $option = null, $value = null)
      {
          if ($option === null) {
              $default = $this->_config;
              $local = isset($this->_keyConfig[$keyname]) ? $this->_keyConfig[$keyname] : [];
  
              return $local + $default;
          }
          if (!is_array($option)) {
              $option = [$option => $value];
          }
          $this->_keyConfig[$keyname] = $option;
  
          return null;
      }
code_tokens: public function configKey ( $ keyname , $ option = null , $ value = null ) { if ( $ option === null ) { $ default = $ this -> _config ; $ local = isset ( $ this -> _keyConfig [ $ keyname ] ) ? $ this -> _keyConfig [ $ keyname ] : [ ] ; return $ local + $ default ; } if ( ! is_array ( $ option ) ) { $ option = [ $ option => $ value ] ; } $ this -> _keyConfig [ $ keyname ] = $ option ; return null ; }
docstring: Set the configuration for a specific top level key.
  
  ### Examples:
  
  Set a single config option for a key:
  
  ```
  $this->Cookie->configKey('User', 'expires', '+3 months');
  ```
  
  Set multiple options:
  
  ```
  $this->Cookie->configKey('User', [
  'expires', '+3 months',
  'httpOnly' => true,
  ]);
  ```
  
  @param string $keyname The top level keyname to configure.
  @param null|string|array $option Either the option name to set, or an array of options to set,
  or null to read config options for a given key.
  @param string|null $value Either the value to set, or empty when $option is an array.
  @return array|null
docstring_tokens: Set the configuration for a specific top level key .