fix issue #213 : CommentedMap.copy() incomplete result

Only the "native" keys were copied, not any of the merged keys.
Now .copy() is implemented and a "flattened" new dict is returned.

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2 files changed, 24 insertions, 0 deletions

diff --git a/_test/test_anchor.py b/_test/test_anchor.py
index 3838833..3a92036 100644
--- a/_test/test_anchor.py
+++ b/_test/test_anchor.py
@@ -396,6 +396,23 @@ class TestMergeKeysValues:
             ref -= 1
         assert len(x) == ref
 
+    def test_issue_213_copy_of_merge(self):
+        from ruamel.yaml import YAML
+        yaml = YAML()
+        d = yaml.load("""\
+        foo: &foo
+          a: a
+        foo2:
+          <<: *foo
+          b: b
+        """)['foo2']
+        assert d['a'] == 'a'
+        d2 = d.copy()
+        assert d2['a'] == 'a'
+        d.pop('a')
+        assert 'a' not in d
+        assert 'a' in d2
+
 
 class TestDuplicateKeyThroughAnchor:
     def test_duplicate_key_00(self):
diff --git a/comments.py b/comments.py
index 84fecbc..88ccea3 100644
--- a/comments.py
+++ b/comments.py
@@ -912,6 +912,13 @@ class CommentedMap(ordereddict, CommentedBase):
             setattr(self, merge_attrib, [])
         return getattr(self, merge_attrib)
 
+    def copy(self):
+        x = {}  # update doesn't work
+        for k, v in self._items():
+            print(k, v)
+            x[k] = v
+        return x
+
     def add_yaml_merge(self, value):
         # type: (Any) -> None
         self.merge.extend(value)