The 'name' argument to the %%cython cell magic is no longer a list.

Added test_cython_name.

IPython/extensions/cythonmagic.py

@@ -147,7 +147,7 b' class CythonMagics(Magics):'
              "multiple times)."
     )
     @magic_arguments.argument(
-        '-n', '--name', action='append', default=[],
+        '-n', '--name',
         help="Specify a name for the Cython module."
     )
     @magic_arguments.argument(
@@ -209,7 +209,7 b' class CythonMagics(Magics):'
             key += time.time(),
 
         if args.name:
-            module_name = str(args.name[0])
+            module_name = str(args.name)
         else:
             module_name = "_cython_magic_" + hashlib.md5(str(key).encode('utf-8')).hexdigest()
         module_path = os.path.join(lib_dir, module_name + self.so_ext)

IPython/extensions/tests/test_cythonmagic.py

@@ -50,6 +50,14 b' def test_cython():'
     nt.assert_equal(ip.user_ns['g'], 20.0)
 
 
+def test_cython_name():
+    # The Cython module named 'mymodule' defines the function f.
+    ip.run_cell_magic('cython', '--name=mymodule', code)
+    # This module can now be imported in the interactive namespace.
+    ip.ex('import mymodule; g = mymodule.f(10)')
+    nt.assert_equal(ip.user_ns['g'], 20.0)
+
+
 @dec.skip_win32
 def test_extlibs():
     code = py3compat.str_to_unicode("""