import stringall_letter = string.ascii_lowercasedef gen_dict():  result = {}  list_num_one = [ a_letter for a_letter in all_letter ]  list_num_two = [ i + j for i in all_letter for j in all_letter[all_letter.find(i)+1:]]  list_num_three = [ i + j + k for i in all_letter            for j in all_letter[all_letter.find(i)+1:]           for k in all_letter[all_letter.find(j)+1:]]  list_num_four = [ i + j + k + l for i in all_letter            for j in all_letter[all_letter.find(i)+1:]           for k in all_letter[all_letter.find(j)+1:]           for l in all_letter[all_letter.find(k)+1:]]  list_num_five = [ i + j + k + l + m for i in all_letter            for j in all_letter[all_letter.find(i)+1:]           for k in all_letter[all_letter.find(j)+1:]           for l in all_letter[all_letter.find(k)+1:]           for m in all_letter[all_letter.find(l)+1:]]  list_num_six = [ i + j + k + l + m + n  for i in all_letter      for j in all_letter[all_letter.find(i)+1:]      for k in all_letter[all_letter.find(j)+1:]      for l in all_letter[all_letter.find(k)+1:]      for m in all_letter[all_letter.find(l)+1:]      for n in all_letter[all_letter.find(m)+1:]      ]  for key,value in enumerate(list_num_one + list_num_two + list_num_three + list_num_four + list_num_five + list_num_six):    result.setdefault(key+1,value)  return result  my_dict = gen_dict()value_to_get = 'abcdef'for key,value in my_dict.iteritems():  if value == value_to_get:    print key