Python How to calculate the quantity by investment and leverage

Hi, I am using python to build an expert advisor. Right now I have a function which calculate the quantity by the investment but dosent take into account the leverage so how I calculate the leverage?

Here is my function:

def qty_buy(symbol, investment, df):
    try:
##        price = float(mt5.symbol_info_tick(symbol).ask)
        price = get_price(df)
        symbol_info = mt5.symbol_info(symbol)._asdict()
        digits = symbol_info['digits']
        min_vol = symbol_info['volume_min']
        max_vol = symbol_info['volume_max']
        vol_steps = symbol_info['volume_step']
        tcs = symbol_info['trade_contract_size']
        tcsv_min = (tcs * price) * min_vol
        tcsv_max = (tcs * price) * max_vol
        pos_qty = []
        qty_value = 0
        if investment < tcsv_min:
            qty = 0
##        elif (investment / price) < min_vol:
##            qty = 0
        elif investment > tcsv_max:
            qty = max_vol
##        elif (investment / price) > max_vol:
##            qty = max_vol
        else:
            for i in np.arange((tcsv_min), (tcsv_max), (vol_steps * price)):
                pos_qty.append(i)
            if len(pos_qty) > 0:
##                qty = find_nearest(pos_qty, (investment / price))
                qty_value = find_nearest(pos_qty, (investment))
            else:
               qty_value = 0
            j = 0
            while j <= int(qty_value):
                if qty_value > (investment):
                    qty_value = qty_value - (vol_steps * price)
                else:
                    break
                j += 1
            qty = qty_value / price
        if qty < min_vol:
            qty = 0
        if '#' in symbol and qty < 50:
            qty = 0
##        print(qty)
##        sys.exit()
        return qty
    except Exception as e:
            print("Error code =",mt5.last_error())
            print(e, 'error ', traceback.format_exc())
            pass

I am taking an investment of 10% of the account_info.margin_free  for testings. I need to add the leverage which is 1:30 with my broker so how do I do this? whats the formula?