How do I make it disappear from the font screen?

# import stand alone modules
import blf
import bpy

font_info = {
    "font_id": 0,
    "handler": None,
}


def init():
    """init function - runs once"""
    import os
    # Create a new font object, use external ttf file.
    font_path = bpy.path.abspath('//Zeyada.ttf')
    # Store the font indice - to use later.
    if os.path.exists(font_path):
        font_info["font_id"] = blf.load(font_path)
    else:
        # Default font.
        font_info["font_id"] = 0

    # set the font drawing routine to run every frame
    font_info["handler"] = bpy.types.SpaceView3D.draw_handler_add(
        draw_callback_px, (None, None), 'WINDOW', 'POST_PIXEL')


def draw_callback_px(self, context):
    """Draw on the viewports"""
    # BLF drawing routine
    font_id = font_info["font_id"]
    blf.position(font_id, 2, 80, 0)
    blf.size(font_id, 50, 72)
    blf.draw(font_id, "Hello World")


if __name__ == '__main__':
    init()

I made a script that displays “Hello World” using this guideline (https://docs.blender.org/api/blender2.8/blf.html) I want to make “Hello World” disappear on the screen when I press ctrl+x. Can you give me some help on how I can code that?
Please give me a brief example.

Save as .py file and install as addon.
ctrl+alt+x - display “Hello World”, ctrl+x - remove it

bl_info = {
    "name": "BLF draw example",
    "author": "",
    "blender": (2, 80, 0),
    "location": "",
    "description": "",
    "warning": "",
    "wiki_url": "",
    "category": "3D View",
}

# import stand alone modules
import blf, bpy, os


font_info = {
    "font_id": 0,
    "handler": None,
}


def init():
    """init function - runs once"""
    # Create a new font object, use external ttf file.
    font_path = bpy.path.abspath('//Zeyada.ttf')
    # Store the font indice - to use later.
    if os.path.exists(font_path):
        font_info["font_id"] = blf.load(font_path)
    else:
        # Default font.
        font_info["font_id"] = 0
        

class VIEW3D_OT_display_blf(bpy.types.Operator):
    '''Description'''
    bl_idname = "view3d.display_blf"
    bl_label = "Display BLF"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        return context.area.type == 'VIEW_3D'
        
    def invoke(self, context, event):
        self.execute(context)
        return {'FINISHED'}

    def execute(self, context):
        # set the font drawing routine to run every frame
        if not font_info["handler"]:
            font_info["handler"] = bpy.types.SpaceView3D.draw_handler_add(draw_callback_px, (None, None), 'WINDOW', 'POST_PIXEL')
            # update viewport
            context.area.tag_redraw()
        return {'FINISHED'}


class VIEW3D_OT_remove_blf(bpy.types.Operator):
    '''Description'''
    bl_idname = "view3d.remove_blf"
    bl_label = "Remove BLF"
    bl_options = {'REGISTER', 'UNDO'}

    @classmethod
    def poll(cls, context):
        return context.area.type == 'VIEW_3D'

    def invoke(self, context, event):
        self.execute(context)
        return {'FINISHED'}

    def execute(self, context):
        if font_info["handler"]:
            bpy.types.SpaceView3D.draw_handler_remove(font_info["handler"], "WINDOW")
            font_info["handler"] = None
            # update viewport
            context.area.tag_redraw()
        return {'FINISHED'}
        
        
def draw_callback_px(self, context):
    """Draw on the viewports"""
    # BLF drawing routine
    font_id = font_info["font_id"]
    blf.position(font_id, 2, 80, 0)
    blf.size(font_id, 50, 72)
    blf.draw(font_id, "Hello World")


addon_keymaps = []


classes = (
    VIEW3D_OT_display_blf,
    VIEW3D_OT_remove_blf
)


def register_keymaps():
    kc = bpy.context.window_manager.keyconfigs.addon
    if kc:
        km = kc.keymaps.new(name="3D View", space_type='VIEW_3D')
   
        kmi = km.keymap_items.new("view3d.remove_blf", 'X', 'PRESS', ctrl=True)
        addon_keymaps.append((km, kmi))
        
        kmi = km.keymap_items.new("view3d.display_blf", 'X', 'PRESS', ctrl=True, alt=True)
        addon_keymaps.append((km, kmi))


def unregister_keymaps():
    for km, kmi in addon_keymaps:
        km.keymap_items.remove(kmi)
    addon_keymaps.clear()


def register():
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)
    register_keymaps()


def unregister():
    from bpy.utils import unregister_class
    for cls in reversed(classes):
        unregister_class(cls)
    unregister_keymaps()


if __name__ == "__main__":
    register()
    init()