def hash_all(strs, digest=None):
 digest = (digest or hashlib.sha1())
 for s in strs:
  digest.update(s)
 return digest.hexdigest()

def hash_all ( strs , digest = None ) : digest = ( digest or hashlib . sha1 ( ) ) for s in strs : digest . update ( s ) return digest . hexdigest ( )
returns a hash of the concatenation of all the strings in strs .