I can't seem to fix the error in this Python code. Can I know what it is? The error seems to appear in the 84th line.

  1  def add(a, b):
  2      return a + b
  3  
  4  # This function subtracts two numbers
  5  def subtract(a, b):
  6      return a - b
  7  
  8  # This function multiplies two numbers
  9  def multiply(a, b):
 10      return a * b
 11  
 12  # This function divides two numbers
 13  def divide(a, b):
 14      return a / b
 15      
 16  # This function displays the power of two numbers
 17  def power(a, b):
 18      return a ^ b
 19  
 20  # This function displays the remainder of two numbers
 21  def remainder(a, b):
 22      return a % b
 23  
 24  #-------------------------------------
 25  #TODO: Write the select_op(choice) function here
 26  #This function sould cover Task 1 (Section 2) and Task 3
 27  
 28  def select_op(choice):
 29      if (choice == "#"):
 30         return -1
 31    
 32      elif (choice in('+','-','*','/','^','%','#','$')):
 33          while true:
 34              firstnum=input("Enter the first number:")
 35              print(firstnum)
 36              try: 
 37                  if firstnum == '0$':
 38                   return 0
 39                  else:
 40                          num1=float(firstnum)
 41              except:
 42                              print("Not a valid number,please enter again")
 43                              continue
 44              secondnum=input("Enter the second number: ")
 45              print(secondnum)
 46              try:
 47                  if secondnum=='0$':
 48                   return 0
 49                  elif secondnum=='#':
 50                    return -1
 51                  else:
 52                       num2=float(secondnum)
 53                  break
 54              except:
 55               print("Not a valid number,please enter again")
 56              continue
 57          if choice =="+":
 58      
 59             print(num1,"+", num2,"=",add(num1,num2))
 60           
 61          elif choice == '-':
 62             print(num1,"-", num2,"=",subtract(num1,num2)) 
 63             
 64          elif choice == '*':
 65             print(num1,"*", num2,"=",multiply(num1,num2)) 
 66             
 67          elif choice == '/':
 68             if num2==0:
 69                 print("float division by zero")
 70                 print(num1,"/",num2,"=", divide(num1,num2))
 71             
 72          elif choice == '^':
 73              num1=int(num1)
 74              num2=int(num2)
 75          print(num1,"^", num2,"=",power(num1,num2)) 
 76          
 77             
 78          elif choice == "%":
 79          print(num1,"%", num2,"=",remainder(num1,num2)) 
 80          elif choice == '$':
 81          return select_op()  
 82          else:
 83          print("Unrecognized operation")
 84  
 85  #End the select_op(choice) function here
 86  #-------------------------------------
 87  #This is the main loop. It covers Task 1 (Section 1)
 88  #YOU DO NOT NEED TO CHANGE ANYTHING BELOW THIS LINE
 89  while True:
 90    print("Select operation.")
 91    print("1.Add      : + ")
 92    print("2.Subtract : - ")
 93    print("3.Multiply : * ")
 94    print("4.Divide   : / ")
 95    print("5.Power    : ^ ")
 96    print("6.Remainder: % ")
 97    print("7.Terminate: # ")
 98    print("8.Reset    : $ ")
 99    
100  
101    # take input from the user
102    choice = input("Enter choice(+,-,*,/,^,%,#,$): ")
103    print(choice)
104    if(select_op(choice) == -1):
105      #program ends here
106      print("Done. Terminating")
107      exit()