diff --git a/ConflictSet.cpp b/ConflictSet.cpp
index ebe88c6..b3555f0 100644
--- a/ConflictSet.cpp
+++ b/ConflictSet.cpp
@@ -2647,17 +2647,27 @@ ConflictSet_check(void *cs, const ConflictSet_ReadRange *reads,
 __attribute__((__visibility__("default"))) void
 ConflictSet_addWrites(void *cs, const ConflictSet_WriteRange *writes, int count,
                       int64_t writeVersion) {
-  auto *impl = ((ConflictSet::Impl *)cs);
+  auto *impl = (ConflictSet::Impl *)cs;
   mallocBytesDelta = 0;
   impl->addWrites(writes, count, writeVersion);
   impl->totalBytes += mallocBytesDelta;
+#if SHOW_MEMORY
+  if (impl->totalBytes != mallocBytes) {
+    abort();
+  }
+#endif
 }
 __attribute__((__visibility__("default"))) void
 ConflictSet_setOldestVersion(void *cs, int64_t oldestVersion) {
-  auto *impl = ((ConflictSet::Impl *)cs);
+  auto *impl = (ConflictSet::Impl *)cs;
   mallocBytesDelta = 0;
   impl->setOldestVersion(oldestVersion);
   impl->totalBytes += mallocBytesDelta;
+#if SHOW_MEMORY
+  if (impl->totalBytes != mallocBytes) {
+    abort();
+  }
+#endif
 }
 __attribute__((__visibility__("default"))) void *
 ConflictSet_create(int64_t oldestVersion) {
diff --git a/SkipList.cpp b/SkipList.cpp
index 6b47a44..ea91c4d 100644
--- a/SkipList.cpp
+++ b/SkipList.cpp
@@ -702,16 +702,35 @@ ConflictSet_check(void *cs, const ConflictSet_ReadRange *reads,
 __attribute__((__visibility__("default"))) void
 ConflictSet_addWrites(void *cs, const ConflictSet_WriteRange *writes, int count,
                       int64_t writeVersion) {
-  ((ConflictSet::Impl *)cs)->addWrites(writes, count, writeVersion);
+  auto *impl = (ConflictSet::Impl *)cs;
+  mallocBytesDelta = 0;
+  impl->addWrites(writes, count, writeVersion);
+  impl->totalBytes += mallocBytesDelta;
+#if SHOW_MEMORY
+  if (impl->totalBytes != mallocBytes) {
+    abort();
+  }
+#endif
 }
 __attribute__((__visibility__("default"))) void
 ConflictSet_setOldestVersion(void *cs, int64_t oldestVersion) {
-  ((ConflictSet::Impl *)cs)->setOldestVersion(oldestVersion);
+  auto *impl = (ConflictSet::Impl *)cs;
+  mallocBytesDelta = 0;
+  impl->setOldestVersion(oldestVersion);
+  impl->totalBytes += mallocBytesDelta;
+#if SHOW_MEMORY
+  if (impl->totalBytes != mallocBytes) {
+    abort();
+  }
+#endif
 }
 __attribute__((__visibility__("default"))) void *
 ConflictSet_create(int64_t oldestVersion) {
-  return new (safe_malloc(sizeof(ConflictSet::Impl)))
+  mallocBytesDelta = 0;
+  auto *result = new (safe_malloc(sizeof(ConflictSet::Impl)))
       ConflictSet::Impl{oldestVersion};
+  result->totalBytes += mallocBytesDelta;
+  return result;
 }
 __attribute__((__visibility__("default"))) void ConflictSet_destroy(void *cs) {
   using Impl = ConflictSet::Impl;
diff --git a/conflict_set.py b/conflict_set.py
index 10c68fa..ccab8c3 100644
--- a/conflict_set.py
+++ b/conflict_set.py
@@ -4,22 +4,6 @@ import os
 
 from typing import Optional
 
-_lib = None
-for f in (
-    os.path.dirname(__file__) + "/build/radix_tree/libconflict-set.so.0",
-    os.path.dirname(__file__) + "/build/radix_tree/libconflict-set.0.dylib",
-):
-    try:
-        _lib = ctypes.cdll.LoadLibrary(f)
-    except:
-        pass
-
-if _lib is None:
-    import sys
-
-    print("Could not find libconflict-set", file=sys.stderr)
-    sys.exit(1)
-
 
 class _Key(ctypes.Structure):
     _fields_ = [("p", ctypes.POINTER(ctypes.c_ubyte)), ("len", ctypes.c_int)]
@@ -37,31 +21,6 @@ class WriteRange(ctypes.Structure):
     _fields_ = [("begin", _Key), ("end", _Key)]
 
 
-_lib.ConflictSet_create.argtypes = (ctypes.c_int64,)
-_lib.ConflictSet_create.restype = ctypes.c_void_p
-
-_lib.ConflictSet_check.argtypes = (
-    ctypes.c_void_p,
-    ctypes.POINTER(ReadRange),
-    ctypes.POINTER(ctypes.c_int),
-    ctypes.c_int,
-)
-
-_lib.ConflictSet_addWrites.argtypes = (
-    ctypes.c_void_p,
-    ctypes.POINTER(WriteRange),
-    ctypes.c_int,
-    ctypes.c_int64,
-)
-
-_lib.ConflictSet_setOldestVersion.argtypes = (ctypes.c_void_p, ctypes.c_int64)
-
-_lib.ConflictSet_destroy.argtypes = (ctypes.c_void_p,)
-
-_lib.ConflictSet_getBytes.argtypes = (ctypes.c_void_p,)
-_lib.ConflictSet_getBytes.restype = ctypes.c_int64
-
-
 class Result(enum.Enum):
     COMMIT = 0
     CONFLICT = 1
@@ -93,34 +52,88 @@ def read(version: int, begin: bytes, end: Optional[bytes] = None) -> ReadRange:
 
 
 class ConflictSet:
-    def __init__(self, version: int = 0) -> None:
-        self.p = _lib.ConflictSet_create(version)
+    def __init__(self, version: int = 0, implementation: Optional[str] = None) -> None:
+        self._lib = None
+        if implementation is None:
+            implementation = "radix_tree"
+        for f in (
+            os.path.dirname(__file__)
+            + "/build/"
+            + implementation
+            + "/libconflict-set.so.0",
+            os.path.dirname(__file__)
+            + "/build/"
+            + implementation
+            + "/libconflict-set.0.dylib",
+        ):
+            try:
+                self._lib = ctypes.cdll.LoadLibrary(f)
+            except:
+                pass
+
+        if self._lib is None:
+            import sys
+
+            print(
+                "Could not find libconflict-set implementation " + implementation,
+                file=sys.stderr,
+            )
+            sys.exit(1)
+
+        self._lib.ConflictSet_create.argtypes = (ctypes.c_int64,)
+        self._lib.ConflictSet_create.restype = ctypes.c_void_p
+
+        self._lib.ConflictSet_check.argtypes = (
+            ctypes.c_void_p,
+            ctypes.POINTER(ReadRange),
+            ctypes.POINTER(ctypes.c_int),
+            ctypes.c_int,
+        )
+
+        self._lib.ConflictSet_addWrites.argtypes = (
+            ctypes.c_void_p,
+            ctypes.POINTER(WriteRange),
+            ctypes.c_int,
+            ctypes.c_int64,
+        )
+
+        self._lib.ConflictSet_setOldestVersion.argtypes = (
+            ctypes.c_void_p,
+            ctypes.c_int64,
+        )
+
+        self._lib.ConflictSet_destroy.argtypes = (ctypes.c_void_p,)
+
+        self._lib.ConflictSet_getBytes.argtypes = (ctypes.c_void_p,)
+        self._lib.ConflictSet_getBytes.restype = ctypes.c_int64
+
+        self.p = self._lib.ConflictSet_create(version)
 
     def addWrites(self, version: int, *writes: WriteRange):
-        _lib.ConflictSet_addWrites(
+        self._lib.ConflictSet_addWrites(
             self.p, (WriteRange * len(writes))(*writes), len(writes), version
         )
 
     def check(self, *reads: ReadRange) -> list[Result]:
         r = (ctypes.c_int * len(reads))()
-        _lib.ConflictSet_check(self.p, *reads, r, 1)
+        self._lib.ConflictSet_check(self.p, *reads, r, 1)
         return [Result(x) for x in r]
 
     def setOldestVersion(self, version: int) -> None:
-        _lib.ConflictSet_setOldestVersion(self.p, version)
+        self._lib.ConflictSet_setOldestVersion(self.p, version)
 
     def getBytes(self) -> int:
-        return _lib.ConflictSet_getBytes(self.p)
+        return self._lib.ConflictSet_getBytes(self.p)
 
     def __enter__(self):
         return self
 
     def close(self) -> None:
         if self.p is not None:
-            _lib.ConflictSet_destroy(self.p)
+            self._lib.ConflictSet_destroy(self.p)
             self.p = None
 
     def __exit__(self, exception_type, exception_value, exception_traceback):
         if self.p is not None:
-            _lib.ConflictSet_destroy(self.p)
+            self._lib.ConflictSet_destroy(self.p)
             self.p = None