Beginner Blender Python Tutorial: Python Classes; step by step version Example 2 (used in tutorial: https://youtu.be/t2KEolkhIoA)

step_by_step_example_2.py

import bpy

#######################################################################
# create a cube with square faces
#######################################################################

# define the coordinates of each vertex
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),
]

# define faces using the indexes of the vertices
faces = [
    (0, 1, 2, 3),
    (7, 6, 5, 4),
    (4, 5, 1, 0),
    (7, 4, 0, 3),
    (6, 7, 3, 2),
    (5, 6, 2, 1),
]

edges = []

# create a mesh from the vert, edge, and face data
mesh_data = bpy.data.meshes.new("cube_data")
mesh_data.from_pydata(verts, edges, faces)

# create a object using the mesh data
mesh_obj = bpy.data.objects.new("cube_object", mesh_data)

bpy.context.collection.objects.link(mesh_obj)

#######################################################################
# create a cube with triangle faces
#######################################################################

# define the coordinates of each vertex
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),
]

# define faces using the indexes of the vertices
faces = [
    (0, 1, 2),
    (0, 2, 3),
    (6, 5, 4),
    (7, 6, 4),
    (4, 5, 1),
    (4, 1, 0),
    (7, 4, 0),
    (7, 0, 3),
    (6, 7, 3),
    (6, 3, 2),
    (5, 6, 2),
    (5, 2, 1),
]

edges = []

# create a mesh from the vert, edge, and face data
mesh_data = bpy.data.meshes.new("cube_data")
mesh_data.from_pydata(verts, edges, faces)

# create a object using the mesh data
mesh_obj = bpy.data.objects.new("cube_object", mesh_data)

bpy.context.collection.objects.link(mesh_obj)

mesh_obj.location.y = 3