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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def urban_lookup(word):
	'''
	Return a Urban Dictionary definition for a word or None if no result was
	found.
	'''
	url = "http://api.urbandictionary.com/v0/define"
	params = dict(term=word)
	resp = requests.get(url, params=params)
	resp.raise_for_status()
	res = resp.json()
	if not res['list']:
		return
	return res['list'][0]['definition']