def variant1(s):
  characters=['_', '*', '[', ']', '(', ')', '~', '`', '>', '#', '+', '-', '=', '|', '{', '}', '.', '!']
  for c in characters:
    s = s.replace(f'{c}', f'\\{c}')
  return s


escaped = "_*[]()~`>#+-=|{}.!"

def escape(c):
   return '\\'+c if c in escaped else c

def variant2(s):
   return ''.join(map(escape, s))


import re

escaped_re = r"[_\*\[\]\(\)\~`\>#\+-=\|\{\}\.!]"

def replace(matchobj):
  return f"\\{matchobj.group(0)}"

def variant3(s):
   return re.sub(escaped_re, replace, s)


test_data = """
Hello! Escape testing (some cases).
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
Hello! Escape testing (some cases).
"""

import time

def measure(f, arg):
   start_time = time.perf_counter_ns()
   result = f(arg)
   print("--- %s ns ---" % (time.perf_counter_ns() - start_time))
   return result

print(measure(variant1, test_data)) # 13900 ns
print(measure(variant2, test_data)) # 66800 ns
print(measure(variant3, test_data)) # 233800 ns