Morse Code Decoder

def interpret(s):
    return interpret2(s,[]) #Calls another fucntion with an extra argument

def interpret2(s, interpreted):
    """s is a morse code. The function return all valid interpretations of the code.
       It uses backtracking for this task (implemented using recursion)."""
 
    if s == "":
        print interpreted

    for j in xrange(len(s)):
        if s[:j + 1] in dict1:
            interpreted.append(dict1[s[:j + 1]])
            interpret2(s[j + 1:], interpreted)

    if len(interpreted) > 0: 
        interpreted.pop()     #when the program gets here, either it has failed to find a valid interpretation, or have 
			      #found one already and printed it; in both cases it needs to backtrack.
    return

dict1 = {'---': 'o', '--.': 'g', '-...': 'b', '-..-': 'x', '.-.': 'r', '--.-': 'q', '--..': 'z', '.--': 'w', '.-': 'a',
         '..': 'i', '-.-.': 'c', '..-.': 'f', '-.--': 'y', '-': 't', '.': 'e', '.-..': 'l', '...': 's', '..-': 'u',
         '-.-': 'k', '-..': 'd', '.---': 'j', '.--.': 'p', '--': 'm', '-.': 'n', '....': 'h', '...-': 'v'}

interpret(".-..---")