Kamon Ayeva <br/><br/>
Mastering Python Design Patterns. 

 - 248. 
<br/><br/>Electronic book text. 
<br/><br/><br/>Data in extended ASCII character set. <br/>Mode of access: Internet. 
<br/><br/><label>ISBN: </label>9781788832069 
<br/><br/><label>Standard No.: </label>9781788832069  isbn