Move __currency into Coins class

bot/coins.py

@@ -7,6 +7,10 @@ from irc3.utils import IrcString
 from . import Plugin
 
 
+
+class Coins(Plugin):
+    API_URL = 'https://api.cryptowat.ch/markets/{market}/{crypto}{currency}/summary'
+
     def __currency(name, prefix=None, suffix=None):
 	def str(value):
 	    return '{prefix}{value:,.2f}{suffix}'.format(
@@ -15,8 +19,6 @@ def __currency(name, prefix=None, suffix=None):
 		    value=value)
 	return str
 
-class Coins(Plugin):
-    API_URL = 'https://api.cryptowat.ch/markets/{market}/{crypto}{currency}/summary'
     CURRENCIES = {
         'usd': __currency('usd', prefix='$'),
         'eur': __currency('eur', suffix='€'),