added property to array interface

Author: jhavl

spatialmath/baseposelist.py

@@ -233,6 +233,15 @@ def arghandler(self, arg, convertfrom=(), check=True):
 
         return True
 
+    @property
+    def __array_interface__(self):
+        """
+        Copies the numpy array interface from the first numpy array
+        so that C extenstions with this spatial math class have direct
+        access to the underlying numpy array
+        """
+        return self.data[0].__array_interface__
+
     @property
     def _A(self):
         """