My-Craft Blender 2.80 Exporter

__init__.py

bl_info = {
    "name": "My-Craft Export (.mce)",
    "description": "NexusNul is cool",
    "author": "NexusNul",
    "version": (2, 0, 0, 0),
    'blender': (2, 80, 0),
    "location": "File > Import-Export",
    "wiki_url": "",
    "category": "Import-Export"}

import bpy
from bpy_extras.io_utils import ExportHelper

class MCEExporter(bpy.types.Operator, ExportHelper):
    bl_idname = "export_scene.mce"
    bl_label = "Export MCE"
    filename_ext = ".mce"

    option_export_selection: bpy.props.BoolProperty(name = "Export Selection Only", description = "Export only selected objects", default = False)

    def Write(self, text):
        self.file.write(text)

    def execute(self, context):
        print("\n#--------------------------------------------------")
        print("# My-Craft Exporter v0.0.1")
        print("#--------------------------------------------------")
        self.file = open(self.filepath, "w")

        self.Write("[")
        # TODO: Write data
        self.Write("]")

        self.file.close()
        print("Finished")
        return {'FINISHED'}

def menu_func(self, context):
    self.layout.operator(MCEExporter.bl_idname, text = "My-Craft (.mce)")

def register():
    bpy.utils.register_class(MCEExporter)
    bpy.types.TOPBAR_MT_file_export.append(menu_func)

def unregister():
    bpy.types.TOPBAR_MT_file_export.remove(menu_func)
    bpy.utils.unregister_class(MCEExporter)

if __name__ == "__main__":
    register()