Fix dict pretty printer in PyPy #9776

+3 tests passing

IPython/lib/pretty.py

@@ -753,7 +753,10 b' _type_pprinters = {'
 }
 
 try:
-    _type_pprinters[types.DictProxyType] = _dict_pprinter_factory('<dictproxy {', '}>')
+    # In PyPy, types.DictProxyType is dict, setting the dictproxy printer
+    # using dict.setdefault avoids overwritting the dict printer
+    _type_pprinters.setdefault(types.DictProxyType,
+                               _dict_pprinter_factory('<dictproxy {', '}>'))
     _type_pprinters[types.ClassType] = _type_pprint
     _type_pprinters[types.SliceType] = _repr_pprint
 except AttributeError: # Python 3