diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
index 5df108f..040c9ff 100644
--- a/.devcontainer/Dockerfile
+++ b/.devcontainer/Dockerfile
@@ -17,6 +17,7 @@ RUN if [ "${REINSTALL_CMAKE_VERSION_FROM_SOURCE}" != "none" ]; then \
 # [Optional] Uncomment this section to install additional packages.
 # RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
 #     && apt-get -y install --no-install-recommends <your-package-list-here>
-RUN apt update && export DEBIAN_FRONTEND=noninteractive && apt -y install clangd-19 clang-tidy-19 python3-pip
+RUN apt update && export DEBIAN_FRONTEND=noninteractive && apt -y install clangd-19 clang-tidy-19 python3-pip python3.12-venv
 RUN update-alternatives --install /usr/bin/clangd clangd /usr/bin/clangd-19 100
 RUN update-alternatives --install /usr/bin/clang-tidy clang-tidy /usr/bin/clang-tidy-19 100
+
diff --git a/py/requirements.txt b/py/requirements.txt
index 321477a..ddf155b 100644
--- a/py/requirements.txt
+++ b/py/requirements.txt
@@ -1,2 +1,2 @@
 semver >= 3.0
-jsonlogic-py == 0.2
+jsonlogic-py == 0.2.1
\ No newline at end of file
diff --git a/py/src/clippy/backends/serialization.py b/py/src/clippy/backends/serialization.py
index 7a8f626..f1f8257 100644
--- a/py/src/clippy/backends/serialization.py
+++ b/py/src/clippy/backends/serialization.py
@@ -118,7 +118,7 @@ def encode_clippy_json(o: Any) -> Any:
     json encoder that is clippy-object aware.
     """
     if isinstance(o, jl.Operand):  # expression or variable
-        return {"expression_type": "jsonlogic", "rule": o.prepare()}
+        return {"expression_type": "jsonlogic", "rule": o._prepare()}
 
     return o
 
diff --git a/py/src/clippy/selectors.py b/py/src/clippy/selectors.py
index 5854606..f30d7c4 100644
--- a/py/src/clippy/selectors.py
+++ b/py/src/clippy/selectors.py
@@ -13,51 +13,51 @@ class Selector(jl.Variable):
 
     def __init__(self, parent: Selector | None, name: str, docstr: str):
         super().__init__(name, docstr)  # op and o2 are None to represent this as a variable.
-        self.parent = parent
-        self.name = name
-        self.fullname: str = self.name if self.parent is None else f"{self.parent.fullname}.{self.name}"
-        self.subselectors: set[Selector] = set()
+        self._parent = parent
+        self._name = name
+        self._fullname: str = self._name if self._parent is None else f"{self._parent._fullname}.{self._name}"
+        self._subselectors: set[Selector] = set()
 
     def __hash__(self):
-        return hash(self.fullname)
+        return hash(self._fullname)
 
-    def prepare(self):
-        return {"var": self.fullname}
+    def _prepare(self):
+        return {"var": self._fullname}
 
-    def hierarchy(self, acc: list[tuple[str, str]] | None = None):
+    def _hierarchy(self, acc: list[tuple[str, str]] | None = None):
         if acc is None:
             acc = []
-        acc.append((self.fullname, self.__doc__ or ""))
-        for subsel in self.subselectors:
-            subsel.hierarchy(acc)
+        acc.append((self._fullname, self.__doc__ or ""))
+        for subsel in self._subselectors:
+            subsel._hierarchy(acc)
         return acc
 
-    def describe(self):
-        hier = self.hierarchy()
+    def _describe(self):
+        hier = self._hierarchy()
         maxlen = max(len(sub_desc[0]) for sub_desc in hier)
         return "\n".join(f"{sub_desc[0]:<{maxlen + 2}} {sub_desc[1]}" for sub_desc in hier)
 
     def __str__(self):
-        return repr(self.prepare())
+        return repr(self._prepare())
 
-    def to_serial(self):
-        return {"var": self.fullname}
+    def _to_serial(self):
+        return {"var": self._fullname}
 
     def _add_subselector(self, name: str, docstr: str):
         """add a subselector to this selector"""
         subsel = Selector(self, name, docstr)
         setattr(self, name, subsel)
-        self.subselectors.add(subsel)
+        self._subselectors.add(subsel)
 
     def _del_subselector(self, name: str):
         delattr(self, name)
-        self.subselectors.remove(getattr(self, name))
+        self._subselectors.remove(getattr(self, name))
 
     def _clear_subselectors(self):
         """removes all subselectors"""
-        for subsel in self.subselectors:
-            delattr(self, subsel.name)
-        self.subselectors = set()
+        for subsel in self._subselectors:
+            delattr(self, subsel._name)
+        self._subselectors = set()
 
     def _import_from_dict(self, d: AnyDict, merge: bool = False):
         """Imports subselectors from a dictionary.