feat: add convenience method to deepcopy a state

src/autora/state.py

@@ -270,6 +270,53 @@ def update(self, **kwargs):
         """
         return self + Delta(**kwargs)
 
+    def copy(self):
+        """
+        Return a deepcopy of the State
+        Examples:
+            >>> @dataclass(frozen=True)
+            ... class DfState(State):
+            ...    q: pd.DataFrame = field(default_factory=pd.DataFrame,
+            ...                            metadata={"delta": "replace",
+            ...                                      "converter": pd.DataFrame})
+            >>> data = pd.DataFrame({'x': [1, 2, 3]})
+            >>> s_1 = DfState(q=data)
+            >>> s_replace = replace(s_1)
+            >>> s_copy = s_1.copy()
+
+            The build in replace method doesn't create a deepcopy:
+            >>> s_1.q is s_replace.q
+            True
+            >>> s_1.q['y'] = [1,2,3]
+            >>> s_replace.q
+               x  y
+            0  1  1
+            1  2  2
+            2  3  3
+
+            But this copy method does:
+            >>> s_1.q is s_copy.q
+            False
+            >>> s_copy.q
+               x
+            0  1
+            1  2
+            2  3
+
+
+        """
+        # Create a dictionary to hold the field copies
+        field_copies = {}
+
+        # Iterate over all fields of the class
+        for _field in fields(self):
+            value = getattr(self, _field.name)
+            # Use deepcopy to ensure that mutable fields are also copied
+            field_copies[_field.name] = copy.deepcopy(value)
+
+        # Use replace with **field_copies to create a new instance of the same class
+        return replace(self, **field_copies)
+
 
 def _get_value(f, other: Union[Delta, Mapping]):
     """