diff --git a/gpu4pyscf/gto/int3c1e.py b/gpu4pyscf/gto/int3c1e.py
index bdc4516c..591297d4 100644
--- a/gpu4pyscf/gto/int3c1e.py
+++ b/gpu4pyscf/gto/int3c1e.py
@@ -453,7 +453,7 @@ def get_int3c1e_density_contracted(mol, grids, charge_exponents, dm, intopt):
     return int3c_density_contracted
 
 def int1e_grids(mol, grids, charge_exponents=None, dm=None, charges=None, direct_scf_tol=1e-13, intopt=None):
-    '''
+    r'''
     This function computes
     $$\left(\mu \middle| \frac{1}{|\vec{r} - \vec{C}|} \middle| \nu\right)$$
 
diff --git a/gpu4pyscf/gto/int3c1e_ip.py b/gpu4pyscf/gto/int3c1e_ip.py
index 63717d09..aedb7ea9 100644
--- a/gpu4pyscf/gto/int3c1e_ip.py
+++ b/gpu4pyscf/gto/int3c1e_ip.py
@@ -315,7 +315,7 @@ def get_int3c1e_ip2_charge_and_density_contracted(mol, grids, charge_exponents,
     return int3c_ip2
 
 def int1e_grids_ip1(mol, grids, charge_exponents=None, dm=None, charges=None, direct_scf_tol=1e-13, intopt=None):
-    '''
+    r'''
     This function computes
     $$\left(\frac{\partial}{\partial \vec{A}} \mu \middle| \frac{1}{|\vec{r} - \vec{C}|} \middle| \nu\right)$$
     where $\mu(\vec{r})$ centers at $\vec{A}$ and $\nu(\vec{r})$ centers at $\vec{B}$.
@@ -325,7 +325,8 @@ def int1e_grids_ip1(mol, grids, charge_exponents=None, dm=None, charges=None, di
     where $q_C$ is the charge centered at $\vec{C}$.
 
     If charges is not None and dm is not None, the function computes the following contraction:
-    $$\sum_\nu^{n_{ao}} D_{\mu\nu} \sum_{C}^{n_{charge}} q_C \left(\frac{\partial}{\partial \vec{A}} \mu \middle| \frac{1}{|\vec{r} - \vec{C}|} \middle| \nu\right)$$
+    $$\sum_\nu^{n_{ao}} D_{\mu\nu} \sum_{C}^{n_{charge}} q_C
+        \left(\frac{\partial}{\partial \vec{A}} \mu \middle| \frac{1}{|\vec{r} - \vec{C}|} \middle| \nu\right)$$
     '''
     assert grids is not None
 
@@ -348,7 +349,7 @@ def int1e_grids_ip1(mol, grids, charge_exponents=None, dm=None, charges=None, di
             return get_int3c1e_ip1_charge_contracted(mol, grids, charge_exponents, charges, intopt)
 
 def int1e_grids_ip2(mol, grids, charge_exponents=None, dm=None, charges=None, direct_scf_tol=1e-13, intopt=None):
-    '''
+    r'''
     This function computes
     $$\left(\mu \middle| \frac{\partial}{\partial \vec{C}} \frac{1}{|\vec{r} - \vec{C}|} \middle| \nu\right)$$
     where $\mu(\vec{r})$ centers at $\vec{A}$ and $\nu(\vec{r})$ centers at $\vec{B}$.
diff --git a/gpu4pyscf/gto/tests/test_int1e_grids.py b/gpu4pyscf/gto/tests/test_int1e_grids.py
index 5401b216..536cf0e5 100644
--- a/gpu4pyscf/gto/tests/test_int1e_grids.py
+++ b/gpu4pyscf/gto/tests/test_int1e_grids.py
@@ -263,7 +263,7 @@ def test_int1e_grids_charge_contracted_guassian_charge_omega(self):
 
     # Multiple inputs
 
-    def test_int1e_grids_density_contracted_sph_asymmetric(self):
+    def test_int1e_grids_multiple_density_contracted(self):
         np.random.seed(12348)
         n_dm = 4
         dm = np.random.uniform(-2.0, 2.0, (n_dm, mol_sph.nao, mol_sph.nao))
@@ -274,7 +274,7 @@ def test_int1e_grids_density_contracted_sph_asymmetric(self):
         assert isinstance(test_int1e_dot_D, cp.ndarray)
         cp.testing.assert_allclose(ref_int1e_dot_D, test_int1e_dot_D, atol = density_contraction_threshold)
 
-    def test_int1e_grids_charge_contracted_sph(self):
+    def test_int1e_grids_multiple_charge_contracted(self):
         np.random.seed(12348)
         n_charges = 4
         charges = np.random.uniform(-2.0, 2.0, (n_charges, grid_points.shape[0]))
diff --git a/gpu4pyscf/qmmm/chelpg.py b/gpu4pyscf/qmmm/chelpg.py
index c0d44af7..c667fdd7 100644
--- a/gpu4pyscf/qmmm/chelpg.py
+++ b/gpu4pyscf/qmmm/chelpg.py
@@ -99,7 +99,6 @@ def tau_f(R, Rcut, Roff):
     r_pX = np.delete(r_pX, idx, axis=1)
     gridcoords = np.delete(gridcoords, idx, axis=0)
 
-    ngrids = gridcoords.shape[0]
     r_pX = cupy.array(r_pX)
     r_pX_potential = 1/r_pX
     potential_real = cupy.dot(cupy.array(mf.mol.atom_charges()), r_pX_potential)