Best approach completing this table using docxtpl template/python (Border attribute)

i have a table with a fixed number of columns but an undefined number of rows (until its populated) I am able to modify some example code to dynamically enter the rows but I can figure out how to apply the table styling; specifically the boarder properties. I would like the thicker grey outline of the table to continue around the left hand side and bottom. Can anyone point me in the right direction please?

tpl = DocxTemplate('G:\ELECSUPP\Documentation\Results\Kaya Marks/dynamic_table_tpl.docx')

context = {
    'col_labels': ['Description', 'Company Number', 'Calibration \nDue Date'],
    'tbl_contents': [
        {'label': '1', 'cols': ['Desc', 'BXXXXXX', '12/12/21']},
        {'label': '2', 'cols': ['Desc', 'BXXXXXX', '10/01/22']},
        {'label': '3', 'cols': ['Desc', 'BXXXXXX', '10/10/10']},  
    ],
}