old_contents: from helpers import *
  
  calc_users        = open_json_file("calc", [])
  math_operators    = ["+", "-", "*", "/", "&", "|"]
  ignore_operators  = ["**", "&&", "||"] # ** may be too intensive, the others cause syntax errors
  calc_perm = "utils.calc"
  
  
  def calc(text):
      """
      extracts a mathematical expression from `text`
      returns (expression, result) or None
      """
      expression = ""
      should_calc = False
      for char in text:
          if char.isdigit() or (should_calc and char in [".", " "]):
              expression += char
          elif char in math_operators:
              # calculation must include at least 1 operator
              should_calc = True
              expression += char
          elif should_calc and char.isalpha():
              # don't include any more text in the calculation
              break
      if should_calc and not any(op in expression for op in ignore_operators):
          try:
              result = str(eval(expression)) # pylint: disable = W0123
          except: # pylint: disable = W0702
              # we can run into all kinds of errors here
              # most probably SyntaxError
              return None
          return (expression, result)
      return None
  
  
  @hook.event("player.AsyncPlayerChatEvent", "monitor")
  def on_calc_chat(event):
      sender = event.getPlayer()
      message = event.getMessage()
      if not event.isCancelled() and uid(sender) in calc_users and sender.hasPermission(calc_perm):
          output = calc(message)
          if output:
              msg(sender, "&2=== Calc: &e" + output[0] + " &2= &c" + output[1])
  
  
  @hook.command("calc", description="Toggles chat calculations")
  def on_calc_command(sender, args):
      plugin_header(sender, "Chat Calculator")
      if not sender.hasPermission(calc_perm):
          noperm(sender)
          return True
      if not checkargs(sender, args, 0, 1):
          return True
      if not is_player(sender):
          msg(sender, "&cYou are not a player!" % sender)
          return True
  
      toggle(sender, calc_users, name = "Calc")
      save_json_file("calc", calc_users)
  
      status = "enabled" if uid(sender) in calc_users  else "disabled"
      msg(sender, "&6We just &e%s&6 Chat Calculator for you!" % status)
  
      return True
new_contents: from helpers import *
  
  calc_users        = open_json_file("calc", [])
  math_operators    = ["+", "-", "*", "/", "&", "|"]
  ignore_operators  = ["**", "&&", "||"] # ** may be too intensive, the others cause syntax errors
  calc_perm = "utils.calc"
  
  
  def calc(text):
      """
      extracts a mathematical expression from `text`
      returns (expression, result) or None
      """
      expression = ""
      should_calc = False
      for char in text:
          if char.isdigit() or (should_calc and char in [".", " "]):
              expression += char
          elif char in math_operators:
              # calculation must include at least 1 operator
              should_calc = True
              expression += char
          elif should_calc and char.isalpha():
              # don't include any more text in the calculation
              break
      if should_calc and not any(op in expression for op in ignore_operators):
          try:
              result = str(eval(expression)) # pylint: disable = W0123
          except: # pylint: disable = W0702
              # we can run into all kinds of errors here
              # most probably SyntaxError
              return None
          return (expression, result)
      return None
  
  
  @hook.event("player.AsyncPlayerChatEvent", "monitor")
  def on_calc_chat(event):
      sender = event.getPlayer()
      message = event.getMessage()
      if not event.isCancelled() and uid(sender) in calc_users and sender.hasPermission(calc_perm):
          output = calc(message)
          if output:
              msg(sender, "&2=== Calc: &e" + output[0] + " &2= &c" + output[1])
  
  
  @hook.command("calc", description="Toggles chat calculations")
  def on_calc_command(sender, args):
      plugin_header(sender, "Chat Calculator")
      if not sender.hasPermission(calc_perm):
          noperm(sender)
          return True
      if not checkargs(sender, args, 0, 1):
          return True
      if not is_player(sender):
          msg(sender, "&cYou are not a player!" % sender)
          return True
  
      toggle(sender, calc_users, name = "Calc")
      save_json_file("calc", calc_users)
  
      return True
subject: delete duplicate chat message