Update README.md

Author: gorgitko

README.md

@@ -37,7 +37,7 @@ kv = KeyValues(mapper=)
 
 Instance's attribute `mapper_type` will be set to type of passed `mapper=` object.
 
-All these instantiation variants have common optional parameter `key_sorter=`. It's a sorting function which will be applied to keys when you use methods `dump()` or `write()` (or `print(kv)`, which is in fact shortcut for `print(kv.dump())`). For example you can use `key_sorter=sorted` and keys will be represented in alphabetical ascending order; `key_sorter=reversed` for reverse order. **Instance's attribute**. Default: `None`
+All these instantiation variants have common optional parameter `key_sorter=`. It's a sorting function which will be applied to keys of every subpart when you use methods `dump()` or `write()` (or `print(kv)`, which is in fact shortcut for `print(kv.dump())`). For example you can use `key_sorter=sorted` and keys will be represented in alphabetical ascending order; `key_sorter=reversed` for reverse order. **Instance's attribute**. Default: `None`
 
 ### Methods
 * `parse(filename)` - parses the VDF file to `dict` interface representation, i.e. KeyValues can be accessed and modified by `kv[key] = value` operations. Optional arguments: