一旦我的函数被嵌套并相互引用，我的元组就会返回 NoneType 错误，为什么？

如何解决一旦我的函数被嵌套并相互引用，我的元组就会返回 NoneType 错误，为什么？

我编写了函数来调用和替换字典中的元组。所有功能都独立工作。当我单独运行它们时，元组值按计划返回整数。当按顺序运行或与其他函数嵌套时，元组返回 NoneType 错误。当我在被调用的元组上运行 type 时，它​​返回整数。我很困惑，想在转换为类结构来整理之前解决这个问题。

我目前的工作流程是：接受一个由以前的代码（体积）确定的整数>有条件地选择一个除数>向下舍入该值>匹配字典中的值>从字典中返回值>新元组创建>元组输入字典被替换

TypeError                                 Traceback (most recent call last)
<ipython-input-23-1f1ae48bdda3> in <module>
----> 1 asp_master(275,dict_tuberack1,vol_tuberack1,tuberack1,'A1')
      2 height_a1= get_height(dict_tuberack1,'A1')
      3 asp_a(275,height_a1,tuberack1['A1'])
      4 disp_master(275,'A2')
      5 height_a2= get_height(dict_tuberack1,'A2')

<ipython-input-10-ba8bc2194a15> in asp_master(volume,dict_vol,dict_labware,labware,well)
      1 def asp_master(volume,well):
----> 2     if low_vol_check(volume,well)==True:
      3         new_vol=volume_sub(volume,well)
      4         tup_update_sub(new_vol,well)
      5         print(dict_labware[labware[well]])

<ipython-input-16-a23165d51020> in low_vol_check(volume,well)
     10 
     11 def low_vol_check(volume,well):
---> 12     x=get_volume(dict_labware,well)
     13     y=volume
     14     if  x-y < 0:

<ipython-input-16-a23165d51020> in get_volume(dict_labware,well)
      1 def get_volume(dict_labware,well):
      2     tup = dict_labware.get(labware[well])
----> 3     (tup_v,tup_h)=tup
      4     volume=tup_v
      5     return tup_v

TypeError: cannot unpack non-iterable NoneType object

机器人代码：

from opentrons import protocol_api
from opentrons.simulate import get_protocol_api
from math import floor,ceil
from datetime import datetime
import opentrons

protocol = get_protocol_api('2.8')

tuberack1 = protocol.load_labware('opentrons_15_tuberack_nest_15ml_conical','2','tuberack1')
tuberack2 = protocol.load_labware('opentrons_24_tuberack_nest_1.5ml_snapcap','3','tuberack2')
tiprack= protocol.load_labware('opentrons_96_tiprack_300ul','4')
p300 = protocol.load_instrument('p300_single','left',tip_racks=[tiprack])
p300.home

代码：

dict_tuberack1={tuberack1['A1']:(14000,104),tuberack1['A2']:(14000,tuberack1['A3']:(14000,}
vol_tuberack1= {14000: 104,13500: 101,13000: 98,12500: 94,12000: 91,11500: 88,11000: 85,10500: 81,10000: 78,9500: 75,9000: 72,8500: 68,8000: 65,7500: 62,7000: 59,6500: 55,6000: 52,5500: 49,}

def get_volume(dict_labware,well):
    tup = dict_labware.get(labware[well])
    (tup_v,tup_h)=tup
    volume=tup_v
    return tup_v

def low_vol_check(volume,well):
    x=get_volume(dict_labware,well)
    y=volume
    if  x-y < 0:
        return False
    else:
        return True
def tup_update_sub(volume,well):
    tup = dict_labware.get(labware[well])
    adj_list=list(tup)
    adj_list[0]=volume
    divisor=1
    if volume >=1000:
        divisor=1000
        vol_even=round_down(volume,divisor)
    elif 100 <= volume <1000: #this was the issue and was fixed.
        divisor=100
        vol_even=round_down(volume,divisor)
    else:
        divisor=10
        vol_even=round_down(volume,divisor)    

    new_height=dict_vol.get(vol_even)
    adj_list[1]=new_height

    new_tup=tuple(adj_list)
    dict_labware[labware[well]] = new_tup

def asp_master(volume,well):
    if low_vol_check(volume,well)==True:
        new_vol=volume_sub(volume,well)
        tup_update_sub(new_vol,well)
        print(dict_labware[labware[well]])
    else:
        print('Cannot aspirate')  

#robot commands below
def asp_a (volume,height,source):
    p300.pick_up_tip()
    p300.aspirate(volume,source.bottom(z=height))

def disp_a (volume,destination):
    p300.dispense(volume,destination.bottom(z=height+8))
    p300.blowout(height+8)

#code that generated error message below
asp_master(275,'A1')
height_a1= get_height(dict_tuberack1,'A1')
asp_a(275,tuberack1['A1'])