Exception in OOP version of First Triangle in Python, OpenGL 1.5, GLFW

main.py

import glfw
from OpenGL.GL import *
import numpy as np


class Window:
    def __init__(self, width: int, height: int, title: str):
        # Initializing glfw library
        if not glfw.init():
            raise Exception("glfw can not be initialized!")

        # Creating the window
        self._window = glfw.create_window(width, height, title, None, None)

        # Check if window was created
        if not self._window:
            glfw.terminate()
            raise Exception("glfw window can not be created!")

        # set window's position
        glfw.set_window_pos(self._window, 400, 200)

        # Make the context current
        glfw.make_context_current(self._window)

        vertices = [-0.5, -0.5, 0.0,
                    0.5, -0.5, 0.0,
                    0.0, 0.5, 0.0]

        colors = [1.0, 0.0, 0.0,
                  0.0, 1.0, 0.0,
                  0.0, 0.0, 1.0]

        vertices = np.array(vertices, dtype=np.float32)
        colors = np.array(colors, dtype=np.float32)

        glEnableClientState(GL_VERTEX_ARRAY)
        glVertexPointer(3, GL_FLOAT, 0, vertices)

        glEnableClientState(GL_COLOR_ARRAY)
        glVertexPointer(3, GL_FLOAT, 0, colors)

        glClearColor(0, 0.1, 0.1, 1)

    def main_loop(self):
        # The main application loop
        while not glfw.window_should_close(self._window):
            glfw.poll_events()
            glClear(GL_COLOR_BUFFER_BIT)

            glDrawArrays(GL_TRIANGLES, 0, 3)

            glfw.swap_buffers(self._window)

        # terminate glfw, free up allocated resources
        glfw.terminate()


if __name__ == "__main__":
    win = Window(800, 600, "My OpenGL Window")
    win.main_loop()

I found my mistake here:
glEnableClientState(GL_COLOR_ARRAY)
glVertexPointer(3, GL_FLOAT, 0, colors)
I need to replace glVertexPointer to glColorPointer.

Tutorial by Attila Toth: https://www.youtube.com/watch?v=sUJo9KXFzAM&list=PL1P11yPQAo7opIg8r-4BMfh1Z_dCOfI0y&index=2