如何在并发运行的函数中一次执行部分代码?

So, let me give you a brief of what am trying to achieve. I've a command called apply, as soon as some one enters that command, execution of apply function begins. Now, apply function have some part of code which I want to be executed concurrently in case if many users triggered that command at the same time, and there is a async function called register which I want to be executed once at a time. Here's the glimpse of the code:

@client.command()
async def apply(ctx):
 #Stuff I want to be run concurrently
 await register(ctx.author)

async def register(user):
 # I've an another python file 'db.py' for accessing the database 
 data = await db.execute_query('SELECT Total_Reg from Data WHERE rowid = 1')
 total = data[0][0] # Getting the total registrations value and storing it in total variable     
 if total >= max_reg: # If total reg. are more or equal to max value then close the reg.
  print("Registrations are closed!")
  return
 # Otherwise if registrations are open then increase the value of total reg by 1
 # And register the user with unique registration number [reg_no] allotted to him
 await db.execute_query('UPDATE Data SET Total_Reg = Total_Reg + 1 WHERE rowid = 1')
 reg_no = total + 1
 registrations[reg_no] = user
 await close_registration() 
 """Also, in case of Queue or execution of this function once at a time, I 
    want this function to continue executing the code and shouldn't wait for 
    this line of code particularly, i.e await close_registration() should 
    keep on executing in background without blocking the current execution of 
    this function. So should I use asyncio.ensure_future(close_registration()) 
    instead of await or what?"""

我希望你明白我想在这里做什么.现在，让我们来看看我的问题.apply 函数在有人输入 apply 命令时被不和谐触发，因此可能存在 data = await db.execute_query('SELECT Total_Reg fromData WHERE rowid = 1') 可以同时执行多次，这将导致返回相同数量的注册，并存储在所有这些变量的总变量中.

@commands.max_concurrency(1, commands.BucketType.guild, True)
@commands.command() or #@bot.command() depends on what you are using
async def apply(ctx):
    #command here

@commands.command(hidden=True)
@commands.max_concurrency(1, commands.BucketType.guild, True)
async def register(ctx, args):
   #do stuff

@commands.command()
async def apply(args):
   ctx.command = bot.get_command('register')
   await bot.invoke(ctx)