test: fixing wrong curie prefix expectation

CURIE prefixes can start with an underscore ('_'). This patch adds a
test case to validate it.

Signed-off-by: Silvano Cirujano Cuesta <[email protected]>

Author: Silvanoc

tests/test_utils/test_metamodelcore.py

@@ -62,6 +62,7 @@ def test_curie(self):
         self.assertTrue(Curie.is_valid("type"))
         self.assertEqual(":type", Curie(":type"))
         self.assertTrue(Curie.is_valid(':type'))
+        self.assertTrue(Curie.is_valid('_abc:123'))
         self.assertTrue(Curie.is_valid('WIKIDATA_PROPERTY:P854'))
         self.assertTrue(Curie.is_valid('WIKIDATA.PROPERTY:P854'))
         with self.assertRaises(ValueError):