Hello world Blender

hello.py

"""Hello world blender addon.

Adds a "Hello" to the tools section in Blender.
"""

import bpy


class HelloWorldPanel(bpy.types.Panel):
    """Creates a Panel in the Object properties window"""
    bl_label = "Hello World Panel"
    bl_idname = "OBJECT_PT_hello"
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'UI'
    bl_category = "Hello"

    def draw(self, context):
        self.layout.label(text="Hello world!", icon='WORLD_DATA')

def register():
    bpy.utils.register_class(HelloWorldPanel)


def unregister():
    bpy.utils.unregister_class(HelloWorldPanel)