New method is_vtype and exposing again VType at package level

Author: Sylvain MARIE

vtypes/__init__.py

@@ -2,9 +2,9 @@
 #
 #  Copyright (c) Schneider Electric Industries, 2020. All right reserved.
 
-from vtypes.core import vtype
+from vtypes.core import vtype, is_vtype, VType
 
 __all__ = [
     'core',
-    'vtype'
+    'vtype', 'is_vtype', 'VType'
 ]

vtypes/core.py

@@ -473,3 +473,20 @@ def _get_callerframe(offset=0):
     for _ in range(2 + offset):
         frame = frame.f_back
     return frame
+
+
+def is_vtype(t  # type: Any
+             ):
+    # type: (...) -> bool
+    """
+    Returns `True` if `t` is a `VType`, `False` otherwise.
+    It is equivalent to `isinstance(t, VTypeMeta)` or `issubclass(t, VType)`, with exception catching.
+
+    :param t:
+    :return:
+    """
+    # noinspection PyBroadException
+    try:
+        return isinstance(t, VTypeMeta)
+    except Exception:
+        return False