as_a_func.py

import bpy
import bmesh

verts = [
    (1.0, 1.0, -1.0),
    (1.0, -1.0, -1.0),
    (-1.0, -1.0, -1.0),
    (-1.0, 1.0, -1.0),
    (1.0, 1.0, 1.0),
    (1.0, -1.0, 1.0),
    (-1.0, -1.0, 1.0),
    (-1.0, 1.0, 1.0)]

faces = [
    (0, 1, 2, 3),
    (4, 5, 6, 7),  # reversed
    (0, 4, 5, 1),
    (1, 5, 6, 2),
    (2, 6, 7, 3),
    (4, 0, 3, 7)]

def make_object(name, verts, faces, normal_recalc=True):

    scn = bpy.context.scene

    mesh = bpy.data.meshes.new(name + "_Mesh")
    mesh.from_pydata(verts, [], faces) 
    mesh.update()

    if normal_recalc:
        bm = bmesh.new()
        bm.from_mesh(mesh)
        bmesh.ops.recalc_face_normals(bm, faces=bm.faces)
        bm.to_mesh(mesh)
        bm.free()

    ob = bpy.data.objects.new(name, mesh)
    scn.objects.link(ob)

make_object('my_cube', verts, faces)
# make_object(name, verts, faces, normal_recalc=False)