Add operation __index__ and __complex__

Author: antonwolfy

dpnp/dpnp_array.py

@@ -140,7 +140,10 @@ def __bool__(self):
         return self._array_obj.__bool__()
 
  # '__class__',
- # '__complex__',
+ 
+    def __complex__(self):
+        return self._array_obj.__complex__()
+
  # '__contains__',
  # '__copy__',
  # '__deepcopy__',
@@ -187,7 +190,10 @@ def __gt__(self, other):
  # '__imatmul__',
  # '__imod__',
  # '__imul__',
- # '__index__',
+ 
+    def __index__(self):
+        return self._array_obj.__index__()
+
  # '__init__',
  # '__init_subclass__',