diff --git a/development/mac-kdk/parse_pbzx2.py b/development/mac-kdk/parse_pbzx2.py
index 5e56c9933..173a4d648 100644
--- a/development/mac-kdk/parse_pbzx2.py
+++ b/development/mac-kdk/parse_pbzx2.py
@@ -17,6 +17,7 @@ def seekread(f, offset = None, length = 0, relative = True):
         f.seek(offset, [0, 1, 2][relative])
     if length:
         return f.read(length)
+    return None
 
 
 def parse_pbzx(pbzx_path):
@@ -64,10 +65,6 @@ def parse_pbzx(pbzx_path):
                     xar_f.write(f_content)
                     if tail != 'YZ':
                         raise RuntimeError("Error: Footer is not xar file footer")
-    try:
-        xar_f.close()
-    except IOError:
-        pass
 
 
 def main():
diff --git a/volatility3/framework/layers/vmware.py b/volatility3/framework/layers/vmware.py
index ae4a7d55e..61b13eb88 100644
--- a/volatility3/framework/layers/vmware.py
+++ b/volatility3/framework/layers/vmware.py
@@ -154,7 +154,8 @@ class VmwareStacker(interfaces.automagic.StackerLayerInterface):
 
             vmss_success = False
             with contextlib.suppress(IOError):
-                _ = resources.ResourceAccessor().open(vmss).read(10)
+                with resources.ResourceAccessor().open(vmss) as fp:
+                    _ = fp.read(10)
                 context.config[interfaces.configuration.path_join(current_config_path, "location")] = vmss
                 context.layers.add_layer(physical.FileLayer(context, current_config_path, current_layer_name))
                 vmss_success = True
diff --git a/volatility3/framework/objects/__init__.py b/volatility3/framework/objects/__init__.py
index 4334f9d74..2b026ccd1 100644
--- a/volatility3/framework/objects/__init__.py
+++ b/volatility3/framework/objects/__init__.py
@@ -747,10 +747,8 @@ class AggregateType(interfaces.objects.ObjectInterface):
             if isinstance(cls, agg_type):
                 agg_name = agg_type.__name__
 
-        assert isinstance(members, collections.abc.Mapping)
-        f"{agg_name} members parameter must be a mapping: {type(members)}"
-        assert all([(isinstance(member, tuple) and len(member) == 2) for member in members.values()])
-        f"{agg_name} members must be a tuple of relative_offsets and templates"
+        assert isinstance(members, collections.abc.Mapping), f"{agg_name} members parameter must be a mapping: {type(members)}"
+        assert all([(isinstance(member, tuple) and len(member) == 2) for member in members.values()]), f"{agg_name} members must be a tuple of relative_offsets and templates"
 
     def member(self, attr: str = 'member') -> object:
         """Specifically named method for retrieving members."""
diff --git a/volatility3/framework/plugins/windows/registry/userassist.py b/volatility3/framework/plugins/windows/registry/userassist.py
index 30b5db695..f31b7832e 100644
--- a/volatility3/framework/plugins/windows/registry/userassist.py
+++ b/volatility3/framework/plugins/windows/registry/userassist.py
@@ -33,7 +33,11 @@ class UserAssist(interfaces.plugins.PluginInterface):
         self._reg_table_name = None
         self._win7 = None
         # taken from http://msdn.microsoft.com/en-us/library/dd378457%28v=vs.85%29.aspx
-        self._folder_guids = json.load(open(os.path.join(os.path.dirname(__file__), "userassist.json"), "rb"))
+        try:
+            with open(os.path.join(os.path.dirname(__file__), "userassist.json"), "rb") as fp:
+                self._folder_guids = json.load(fp)
+        except IOError:
+            vollog.error("Usersassist data file not found")
 
     @classmethod
     def get_requirements(cls) -> List[interfaces.configuration.RequirementInterface]:
diff --git a/volatility3/framework/symbols/linux/extensions/__init__.py b/volatility3/framework/symbols/linux/extensions/__init__.py
index b47013c5d..ce002b905 100644
--- a/volatility3/framework/symbols/linux/extensions/__init__.py
+++ b/volatility3/framework/symbols/linux/extensions/__init__.py
@@ -128,7 +128,7 @@ class module(generic.GenericIntelProcess):
             sym_addr = sym.st_value
             if wanted_sym_name == sym_name:
                 return sym_addr
-        return # Generation finished
+        return None
 
     @property
     def section_symtab(self):
diff --git a/volatility3/framework/symbols/windows/pdbconv.py b/volatility3/framework/symbols/windows/pdbconv.py
index 15b5c733a..d7d171ce1 100644
--- a/volatility3/framework/symbols/windows/pdbconv.py
+++ b/volatility3/framework/symbols/windows/pdbconv.py
@@ -934,6 +934,7 @@ class PdbRetreiver:
         if progress_callback is not None:
             progress_callback(100, f"Downloading {url + suffix}")
         if result is None:
+            result.close()
             return None
         return url + suffix