Write a Python program to find the first appearance of the substring "not" and "poor" from a given string, if "not" follows the "poor", replace the whole "not"..."poor" substring with "good". Return the resulting string.

def not_poor(str1):
  snot = str1.find('not')
  spoor = str1.find('poor')
  

  if spoor > snot and snot>0 and spoor>0:
    str1 = str1.replace(str1[snot:(spoor+4)], 'good')
    return str1
  else:
    return str1
print(not_poor('The lyrics is not that poor!'))
print(not_poor('The lyrics is poor!'))