from setuptools import setup

setup(name="Demo",
      packages=["orangedemo"],
      package_data={"orangedemo": ["icons/*.svg"]},
      classifiers=["Example :: Invalid"],
      # Declare orangedemo package to contain widgets for the "Demo" category
      entry_points={"orange.widgets": ("Demo = orangedemo")},
      )
from setuptools import setup

setup(name="Demo",
      packages=["orangedemo"],
      package_data={"orangedemo": ["icons/*.svg"]},
      classifiers=["Example :: Invalid"],
      # Declare orangedemo package to contain widgets for the "Demo" category
      entry_points={"orange.widgets": "Demo = orangedemo"},
      )

Remove tuple, since string is sufficient here