How do i upload an image in PO as a document using Python

Hi,

I am trying to upload an image document in the Zoho books purchase order module but the script is not working.

Python script as Follows:

#
#
# Image Capture Start
#
#

app = xw.App(visible=True, add_book=False)
wb = app.books.open(r'C:\Users\Bhavik\OneDrive\Documents\Urban Utility\PO & Bills.xlsx') # Open file
sheet = wb.sheets('Sheet1') # selected sheet
all = sheet.used_range # Get content range
all.api.CopyPicture() # Copy picture area
sheet.api.Paste() # Paste
img_name = 'PO_Bill'
pic = sheet.pictures[0] # Current picture
pic.api.Copy() # Copy the picture
img = ImageGrab.grabclipboard() # Get the picture data of the clipboard
img.save("C:\\Users\\Bhavik\\OneDrive\\Documents\\Urban Utility\\"+img_name + ".png") # Save the picture
pic.delete() # Delete sheet Pictures on
wb.close() # Do not save , Direct closure
app.quit()

# Read Image
# read an image
# screenShot = iio.imread(r'C:\Users\Bhavik\OneDrive\Documents\Urban Utility\PO_Bill.png')
screenShot = open(r'C:\Users\Bhavik\OneDrive\Documents\Urban Utility\PO_Bill.png','r').read
screenS = str(r'C:\Users\Bhavik\OneDrive\Documents\Urban Utility\PO_Bill.png')
# screenShot = Image(url=screenS)
print(screenS)
#
#
# Image Capture End
#
# # Data to be pushed
sku = obj_Json['SKU']
item_id = ''
supplier = obj_Json['Supplier Zoho']
contact_id = ''
reference_number = str(obj_Json['Order Number'])
quantity = obj_Json['Quantity']
rate = obj_Json['Price per pcs RMB']
branch_id = '2486101000005206845'
warehouse_id = '2486101000000107255'
currency_id = '2486101000000000113'
exchange_rate = 0.6
total_amount = obj_Json['Total Amount']
order_date = date.today()
zoho_cost = obj_Json['Zoho Cost']
account_id = '2486101000009226813'
china_Frieght = obj_Json['China Freight'] # JSON Object
# PO Array
line_item_obj=[]
line_item_array = {'item_id' : item_id,
'warehouse_id':warehouse_id,
'quantity' : quantity,
'rate' : rate}
line_item_obj.append(line_item_array)
document_obj = []
document_array = {'file_name': screenS,
'file_type':'png',
'document_id':0}
document_obj.append(document_array)
json_array = {'line_items' : line_item_obj,
'vendor_id': contact_id,
'exchange_rate': exchange_rate,
'date': order_date,
'tax_treatment': tax_treatment,
'branch_id': branch_id,
'reference_number':reference_number,
'currency_id':currency_id,
'documents':document_obj}
json_obj = json.dumps(json_array,default=str)