An simpler reproduce code:

```
import re

NUM = 99

# items = [ '(001)', '(002)', '(003)', ..., '(NUM)']
items = [r'(%03d)' % i for i in range(1, 1+NUM)]
pattern = '|'.join(items)

# repl = '\1\2\3...\NUM'
temp = ('\\' + str(i) for i in range(1, 1+NUM))
repl = ''.join(temp)

text = re.sub(pattern, repl, '(001)')
print(text)

# if NUM == 99
# output: (001)
# if NUM == 100
# output: (001@)
# if NUM == 101
# output: (001@A)
```