code: function(module, name, config, module_storage) {
  
  		this._module = module;
  		this._name = name;
  		this._config = config;
  		this._properties_by_guid = module_storage;
  		if ('is_nullable' in config) this._is_nullable = config.is_nullable;
  
  	}
docs: Create the instance of a field
  @param {Lava.data.Module} module
  @param {string} name Field name
  @param {_cField} config
  @param {object} module_storage Reference to object from module with properties of all records