This python program can not execute due to "break outside the loop"

class dnaString (str): def __new__(self,s): return str.__new__(self,s.upper()) def length (self): return (len(self)) def getATCG (self,num_A,num_T,num_C,num_G): num_A = self.count("A") num_T = self.count("T") num_C = self.count ("C") num_G = self.count ("G") return ( (self.length(), num_A, num_T, num_G, num_C) )

def printnum_A (self): print ("Adenine base content A: {0}".format(self.count("A"))) def printnum_T (self): print ("Adenine base content T: {0}".format(self.count("T"))) def printnum_C (self): print ("Base content C: {0}".format(self.count("C"))) def printnum_G (self): print ("Base content G: {0}".format(self.count("G")))

lines = [] print ("Enter a dns sequence: ") while True: line = input() if line: lines.append(line) else: # hit enter two times break dna = ' '.join(lines)

x=dnaString(dna) x.printnum_T() x.printnum_A()