diff --git a/flopy/modflow/mf.py b/flopy/modflow/mf.py
index 363e4643e4..0dd4eb6e82 100644
--- a/flopy/modflow/mf.py
+++ b/flopy/modflow/mf.py
@@ -240,11 +240,17 @@ def load(f, version='mf2k', exe_name='mf2005.exe',
             print ext_unit_dict
         for key, item in ext_unit_dict.iteritems():
             if item.package is not None:
-                pck = item.package.load(item.filename, ml, ext_unit_dict=ext_unit_dict)
-                pass
+                try:
+                    pck = item.package.load(item.filename, ml, ext_unit_dict=ext_unit_dict)
+                except BaseException as o:
+                    print "[WARNING] - Exception loading {!s} file: {!s}".format(item.filetype, o)
             elif "data" not in item.filetype.lower():
                 if verbose:
                     print "skipping package", item.filetype, item.filename
+            elif "data" in item.filetype.lower():
+                ml.external_fnames.append(item.filename)
+                ml.external_units.append(key)
+                ml.external_binflag.append("binary" in item.filetype.lower())
         return ml
 
 
diff --git a/flopy/modflow/mfdis.py b/flopy/modflow/mfdis.py
index cc1f8a063c..a4cf726655 100644
--- a/flopy/modflow/mfdis.py
+++ b/flopy/modflow/mfdis.py
@@ -145,7 +145,7 @@ def get_cell_volumes(self):
         """
         vol = np.empty((self.nlay, self.nrow, self.ncol))
         for l in range(self.nlay):
-            vol[l,:, :] *= self.get_thickness()[l]
+            vol[l, :, :] *= self.thickness.array[l]
         for r in range(self.nrow):
             vol[:, r, :] *= self.delc[r]
         for c in range(self.ncol):
diff --git a/flopy/modflow/mfoc.py b/flopy/modflow/mfoc.py
index 329e4331f3..eb8762fac1 100644
--- a/flopy/modflow/mfoc.py
+++ b/flopy/modflow/mfoc.py
@@ -368,7 +368,7 @@ def load(f, model, nper=None, ext_unit_dict=None):
         #process each line
         for line in f:
             lnlst = line.strip().split()
-            if line[0] is '#':
+            if line[0] == '#':
                 continue
             
             # added by JJS 12/12/14 to avoid error when there is a blank line in the OC file
diff --git a/flopy/modflow/mfwel.py b/flopy/modflow/mfwel.py
index 496d38925d..dc2c2f2af3 100644
--- a/flopy/modflow/mfwel.py
+++ b/flopy/modflow/mfwel.py
@@ -134,7 +134,7 @@ def write_file(self):
         f_wel.write('%s\n' % self.heading)
         line = (' {0:9d} {1:9d}'.format(self.stress_period_data.mxact, self.ipakcb))
         
-        if self.specify and self.parent.version is 'mfnwt':
+        if self.specify and self.parent.version == 'mfnwt':
           f_wel.write('SPECIFY {0:10.5g} {1:10d}\n'.format(self.phiramp, self.phiramp_unit))
         
         for opt in self.options:
diff --git a/flopy/utils/binaryfile.py b/flopy/utils/binaryfile.py
index 88738d5d5c..ea87f1a066 100644
--- a/flopy/utils/binaryfile.py
+++ b/flopy/utils/binaryfile.py
@@ -8,7 +8,7 @@ class binaryheader():
     """
     def __init__(self, bintype=None, precision='single'):
         floattype = 'f4'
-        if precision is 'double':
+        if precision == 'double':
             floattype = 'f8'
         self.header_types = ['head','ucn']
         if bintype is None:
@@ -173,9 +173,9 @@ def __init__(self, filename, precision, verbose):
         self.recordarray = []
         self.iposarray = []
 
-        if precision is 'single':
+        if precision == 'single':
             self.realtype = np.float32
-        elif precision is 'double':
+        elif precision == 'double':
             self.realtype = np.float64
         else:
             raise Exception('Unknown precision specified: ' + precision)
@@ -463,11 +463,11 @@ def __init__(self, filename, precision='single', verbose=False):
         h1dt = [('kstp', 'i4'), ('kper', 'i4'), ('text', 'a16'),
                 ('ncol', 'i4'), ('nrow', 'i4'), ('nlay', 'i4')]
 
-        if precision is 'single':
+        if precision == 'single':
             self.realtype = np.float32
             h2dt = [('imeth', 'i4'), ('delt', 'f4'), ('pertim', 'f4'),
                     ('totim', 'f4')]
-        elif precision is 'double':
+        elif precision == 'double':
             self.realtype = np.float64
             h2dt = [('imeth', 'i4'),('delt', 'f8'), ('pertim', 'f8'),
                     ('totim', 'f8')]