Replaced python code by XPATH queries.

README.md

@@ -51,42 +51,22 @@ bitdepth_24  = root.xpath('./sound[@bitdepth="24"]')
 Here is how to find all sounds with a 'bang' in them.
 
 ```python
-def sounds_by_crowd_tag(tag):
-    "Find sounds by original tags."
-    for sound in root.iterfind('sound'):
-        tags = [raw.attrib['label'] for raw in sound.xpath('./crowd-tags/tag/raw')]
-        if tag in tags:
-            yield sound
-
-bang_sounds = sounds_by_crowd_tag('bang')
+bang_sounds = root.xpath('./sound[crowd-tags/tag/raw[@label="bang"]]')
 ```
 ##### By their description
 
-We can also use the metadata of the sound to find the recordings you're after. Here is some code to get all the sounds that have a particular word in their description (e.g. 'periodically'):
+We can also use the metadata of the sound to find the recordings you're after. Here is some code to get all the sounds that have a particular word in their description (e.g. 'synth'):
 
 ```python
-def sounds_by_description(word):
-    "Find sounds by their description."
-    for sound in root.iterfind('sound'):
-        description = sound.find('description')
-        if word in description.text:
-            yield sound
-
-sounds_periodically = sounds_by_description("periodically")
+sounds_synth = root.xpath('./sound[description[contains(.,"synth")]]')
 ```
 
 ##### By original tag
 
 Let's look for sounds that the original author tagged 'vintage':
 
 ```python
-def sounds_by_author_tag(tag):
-    "Find sounds by original tags."
-    for sound in root.iterfind('sound'):
-        if sound.xpath('./author-tags/tag[@label="' + tag + '"]'):
-            yield sound
-
-vintage_sounds = sounds_by_author_tag('vintage')
+vintage_sounds = root.xpath('./sound[author-tags/tag[@label="vintage"]]')
 ```
 
 ### Code & Replication