python concat arrays

# Python 3 code to demonstrate list 
# concatenation using + operator  
  
# Initializing lists 
test_list3 = [1, 4, 5, 6, 5] 
test_list4 = [3, 5, 7, 2, 5] 
  
# using + operator to concat 
test_list3 = test_list3 + test_list4 
  
# Printing concatenated list 
print ("Concatenated list using + : "
                   + str(test_list3)) 

listone = [1,2,3]
listtwo = [4,5,6]
mergedlist = []
mergedlist.extend(listone)
mergedlist.extend(listtwo)

listone = [1,2,3]
listtwo = [4,5,6]

joinedlist = listone + listtwo