Fixed TypeError with some VINs (closes idlesign#6)

CHANGELOG

@@ -2,6 +2,11 @@ vininfo changelog
 =================
 
 
+Unreleased
+----------
+* Fixed TypeError with some VINs (closes #6).
+
+
 v1.4.0 [2020-05-02]
 -------------------
 ! Dropped support for Py 2.

tests/test_renault.py

@@ -18,6 +18,8 @@ def test_renault():
     assert '%s' % vin.brand == 'Renault (Renault)'
 
     details = vin.details
+    assert not details.engine
+    assert details.model
     assert details.model.code == 'S'
     assert details.model.name == ['Logan', 'Sandero', 'Duster', 'Dokker', 'Lodgy']
     assert details.body.code == '4'
@@ -27,3 +29,10 @@ def test_renault():
     assert details.transmission.code == '4'
     assert details.transmission.name == 'Manual, 5-Gears'
     assert details.serial.code == '1234567'
+
+
+def test_bogus():
+    vin = Vin('VF1KG1PBE34488860')
+    details = vin.details
+    assert details.engine.code == ''
+    assert not details.engine

vininfo/details/_base.py

@@ -8,7 +8,7 @@
 
 class DetailWrapper:
 
-    __slots__ = ['code', 'name']
+    __slots__ = ['code', 'name', '_supported']
 
     def __init__(self, details: 'VinDetails', detail: 'Detail'):
         """
@@ -17,22 +17,34 @@ def __init__(self, details: 'VinDetails', detail: 'Detail'):
 
         """
         vin = details._vin
-        attr_name, attr_idx = detail.source
-        code_source = getattr(vin, attr_name)
 
-        code = code_source[attr_idx]
+        source = detail.source
+
+        code = ''
+
+        if source:
+            attr_name, attr_idx = source
+            code_source = getattr(vin, attr_name)
+
+            code = code_source[attr_idx]
 
         defs = detail.defs
 
         if callable(defs):
             defs = defs(details)
 
+        self._supported = bool(source)
+        """Flag indicating that this detail extraction is available."""
+
         self.code: str = code
         self.name: Optional[str] = defs.get(code)
 
     def __str__(self):
         return self.name or self.code
 
+    def __bool__(self):
+        return self._supported
+
 
 class Detail:
     """Vin detail descriptor."""