**Tell us what’s happening:**

I have written a code for the arithmetic_arranger project. It runs when I have them in parts but when I run it as a whole program it shows me an error:

" File “/home/runner/UnusedWelllitMarketing/arithmetic_arranger.py”, line 23, in arithmetic_arranger

elif not sign in dict:

TypeError: unhashable type: ‘list’"

**Your code so far**

```
import operator
```

def int_check(num):

if num == int(num):

return True

else:

return False

def arithmetic_arranger(problems, sp=False):

arranged_problems = “”

dict = {"+": operator.add, “-”: operator.sub}

x = 0 #This is the first problem

f1 = [*range(len(problems)) ] #First number of operation is in range of length of first problem

sign = [*range(len(problems))] #sign of operation is in range of length of first problem

f3 = [*range(len(problems)) ] #Second number of operation is in range of length of second problem

for i in problems:

f1 = i.split()

sign = i.split()

f3 = i.split()

if len(problems) > 5:

return “Error: Too many problems”

elif not sign in dict:

print(sign)

return “Error: Operator must be ‘+’ or ‘-’.”

elif not (not int_check(f1) and int_check(f3)):

return “Error: Numbers must only contain digits.”

elif len(f1) > 4 or len(f3) > 4:

return “Error: Numbers cannot be more than four digits.”

x += 1

```
#Format the problems vertically
for i in range(problems):
length = max(len(f1[i]), len(f3[i])) + 2
top = str(f1[i]).rjust(length)
bottom = sign[i] + str(f3[i]).rjust(length - 1)
lines = " "
for s in range(problems):
lines += "-"
if sp:
for i in range(len(problems)):
arranged_problems += top + "\n" + bottom + "\n" + lines
return arranged_problems
```

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.

**Challenge:** Arithmetic Formatter

**Link to the challenge:**