fix import of colour package

sqlalchemy_utils/types/color.py

@@ -5,7 +5,8 @@ from .scalar_coercible import ScalarCoercible
 
 colour = None
 try:
-    from colour import Colour as python_colour_type
+    import colour
+    python_colour_type = colour.Color
 except ImportError:
     python_colour_type = None
 

tests/types/test_color.py

@@ -6,7 +6,7 @@ from sqlalchemy_utils.types import color
 from tests import TestCase
 
 
-@mark.skipif('color.colour is None')
+@mark.skipif('color.python_colour_type is None')
 class TestColorType(TestCase):
     def create_models(self):
         class Document(self.Base):