diff --git a/pyEPR/ansys.py b/pyEPR/ansys.py
index 911dcba..5fa8eee 100644
--- a/pyEPR/ansys.py
+++ b/pyEPR/ansys.py
@@ -1500,7 +1500,7 @@ def _readin_Q3D_matrix(path: str):
                               skipinitialspace=True,
                               index_col=0)
         units = re.findall(r'C Units:(.*?),', text)[0]
-
+        
         if len(s2) > 1:
             df_cond = pd.read_csv(io.StringIO(s2[1].strip()),
                                   delim_whitespace=True,
@@ -1509,6 +1509,7 @@ def _readin_Q3D_matrix(path: str):
             units_cond = re.findall(r'G Units:(.*?)\n', text)[0]
         else:
             df_cond = None
+            units_cond = None
 
         var = re.findall(r'DesignVariation:(.*?)\n',
                          text)  # this changed circa v2020
diff --git a/pyEPR/calcs/back_box_numeric.py b/pyEPR/calcs/back_box_numeric.py
index 8dda6ad..22aeb9d 100644
--- a/pyEPR/calcs/back_box_numeric.py
+++ b/pyEPR/calcs/back_box_numeric.py
@@ -153,8 +153,11 @@ def make_dispersive(H, fock_trunc, fzpfs=None, f0s=None, chi_prime=False,
         [H_lin, H_nl] = H
         H = H_lin + H_nl
     else:  # make sure its a quanutm object
-        assert type(
-            H) == qutip.qobj.Qobj, "Please pass in either a list of Qobjs or Qobj for the Hamiltonian"
+        from qutip import Qobj
+        if not isinstance(H, Qobj): #  Validate that the input is a Qobj instance.
+            raise TypeError("Please pass in either a list of Qobjs or a Qobj for the Hamiltonian")
+        #assert type(
+        #    H) == qutip.qobj.Qobj, "Please pass in either a list of Qobjs or Qobj for the Hamiltonian"
 
     print("Starting the diagonalization")
     evals, evecs = H.eigenstates()
diff --git a/pyEPR/toolbox/plotting.py b/pyEPR/toolbox/plotting.py
index 5a5e08e..5cc9a79 100644
--- a/pyEPR/toolbox/plotting.py
+++ b/pyEPR/toolbox/plotting.py
@@ -97,6 +97,7 @@ def get_color_cycle(n, colormap=None, start=0., stop=1., format='hex'):
     colormap = colormap or default_colormap()
 
     pts = np.linspace(start, stop, n)
+    colors = None
     if format == 'hex':
         colors = [rgb2hex(colormap(pt)) for pt in pts]
     return colors