Improving regex (validating e-mail)

Line 48:
The previous regex ` ^[\w\.\+\-]+\@[\w]+\.[a-z]{2,3}$ ` matched only a small subset of valid e-mail address (e.g.: didn't match domain names longer than 3 chars or user@this-domain.de or user@multiple.level.dom) and needed to be with start (^) and end ($).
This ` [a-zA-Z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-zA-Z0-9!#$%&'*+\/=?^_`{|}~-]+)*@(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])?\.)+[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])? ` is not perfect (e.g: can't match oriental chars), but imho is much more complete. 

Regex tested with several e-mail addresses with Python 3.6.4 and Python 2.7.14 on Linux 4.14.

misp_modules/modules/expansion/otx.py

@@ -45,7 +45,7 @@ def findAll(data, keys):
     return a
 
 def valid_email(email):
-    return bool(re.search(r"^[\w\.\+\-]+\@[\w]+\.[a-z]{2,3}$", email))
+    return bool(re.search(r"[a-zA-Z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-zA-Z0-9!#$%&'*+\/=?^_`{|}~-]+)*@(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])?\.)+[a-zA-Z0-9](?:[a-zA-Z0-9-]*[a-zA-Z0-9])?", email))
 
 def handler(q=False):
     if q is False: