generate_kpoints by length

from ase.calculators.vasp import Vasp
from ase import Atoms, Atom
import os
import pandas as pd
from ase.io import read
from decimal import Decimal
def makeKPOINTS(twoD, MeshType, desired_directory, out_directory, file):
        #Input Variables
    MeshType = MeshType
    TwoDimensional = twoD
    file = file
    input_POSCAR = desired_directory + file
    output_KPOINTS = out_directory + '/KPOINTS'
    Length = 50

    POSCAR = open(input_POSCAR, 'r')
    lines = POSCAR.readlines()
    scale = Decimal.from_float(float(lines[1].split()[0]))

    #Define original lattice vectors

    a1 = lines[2].split()
    a2 = lines[3].split()
    a3 = lines[4].split()

    a11 = scale*Decimal.from_float(float(a1[0]))
    a12 = scale*Decimal.from_float(float(a1[1]))
    a13 = scale*Decimal.from_float(float(a1[2]))

    a21 = scale*Decimal.from_float(float(a2[0]))
    a22 = scale*Decimal.from_float(float(a2[1]))
    a23 = scale*Decimal.from_float(float(a2[2]))

    a31 = scale*Decimal.from_float(float(a3[0]))
    a32 = scale*Decimal.from_float(float(a3[1]))
    a33 = scale*Decimal.from_float(float(a3[2]))

    #Calculate the determinant

    det = a11*(a22*a33-a23*a32)-a12*(a21*a33-a23*a31)+a13*(a21*a32-a22*a31)

    #Calculate reciprocal vectors

    b11 = (a22*a33-a23*a32)/det
    b12 = (a21*a33-a23*a31)/det
    b13 = (a21*a32-a22*a31)/det

    b21 = (a12*a33-a13*a32)/det
    b22 = (a11*a33-a13*a31)/det
    b23 = (a11*a32-a12*a31)/det

    b31 = (a12*a23-a13*a22)/det
    b32 = (a11*a23-a13*a21)/det
    b33 = (a11*a22-a12*a21)/det

    with open(output_KPOINTS, 'w') as file:
        kpoints_x = ''
        kpoints_y = ''
        kpoints_z = ''
        file.write('Automatic mesh\n')
        file.write( '0\n')
        l = Length 
        kpoints_x = round(float(l*Decimal.sqrt(b11*b11+b12*b12+b13*b13)))
        kpoints_y = round(float(l*Decimal.sqrt(b21*b21+b22*b22+b23*b23)))
        kpoints_z = round(float(l*Decimal.sqrt(b31*b31+b32*b32+b33*b33)))
        if TwoDimensional == True:
            kpoints_z =1
        file.write(MeshType + '\n')
        file.write(str(kpoints_x) + " " + str(kpoints_y) + " " + str(kpoints_z))
        # print (kpoints_x, kpoints_y, kpoints_z)
        kp = [kpoints_x, kpoints_y, kpoints_z]
        print(kp)