diff --git a/pyzx/routing/parity_maps.py b/pyzx/routing/parity_maps.py
index f14c8856..72a4d1d7 100644
--- a/pyzx/routing/parity_maps.py
+++ b/pyzx/routing/parity_maps.py
@@ -38,7 +38,8 @@ class CNOT_tracker(Circuit):
 
     def __init__(self, n_qubits: int, **kwargs):
         super().__init__(n_qubits, **kwargs)
-        self.matrix = Mat2(np.identity(n_qubits, dtype=np.int32).tolist())
+        #self.matrix = Mat2(np.identity(n_qubits, dtype=np.int32).tolist())
+        self.matrix = Mat2.id(n_qubits)
         self.row_perm = np.arange(n_qubits)
         self.col_perm = np.arange(n_qubits)
         self.n_qubits = n_qubits
diff --git a/requirements.txt b/requirements.txt
index fc08f5e7..e3f6c3f3 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,4 +11,4 @@ types-tqdm~=4.66
 mypy>=0.990
 nbsphinx~=0.9.3
 sphinxcontrib-svg2pdfconverter>=1.2.2
-lark~=1.1.7
\ No newline at end of file
+lark>=1.2.2
diff --git a/setup.py b/setup.py
index ec10a7b6..2f214183 100644
--- a/setup.py
+++ b/setup.py
@@ -39,6 +39,6 @@
                       "pyperclip>=1.8.1",
                       "tqdm>=4.56.0",
                       "ipywidgets>=7.5,<8",
-                      "lark~=1.1.7"],
+                      "lark>=1.2.2"],
     include_package_data=True,
 )