diff --git a/Lib/imaplib.py b/Lib/imaplib.py
index ef93f734bd0..3ec75a1997b 100644
--- a/Lib/imaplib.py
+++ b/Lib/imaplib.py
@@ -539,7 +539,7 @@ class IMAP4:
         # Mandated responses are ('FLAGS', 'EXISTS', 'RECENT', 'UIDVALIDITY')
         self.untagged_responses = {}    # Flush old responses.
         self.is_readonly = readonly
-        if readonly:
+        if readonly is not None:
             name = 'EXAMINE'
         else:
             name = 'SELECT'
diff --git a/Lib/imputil.py b/Lib/imputil.py
index 65e799cd491..d83b16e20fe 100644
--- a/Lib/imputil.py
+++ b/Lib/imputil.py
@@ -66,7 +66,7 @@ class ImportManager:
 
         # This is the Importer that we use for grabbing stuff from the
         # filesystem. It defines one more method (import_from_dir) for our use.
-        if not fs_imp:
+        if fs_imp is None:
             cls = self.clsFilesystemImporter or _FilesystemImporter
             fs_imp = cls()
         self.fs_imp = fs_imp
diff --git a/Lib/inspect.py b/Lib/inspect.py
index 2f9511a0eef..ecd3fc925dc 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -665,9 +665,9 @@ def formatargspec(args, varargs=None, varkw=None, defaults=None,
         if defaults and i >= firstdefault:
             spec = spec + formatvalue(defaults[i - firstdefault])
         specs.append(spec)
-    if varargs:
+    if varargs is not None:
         specs.append(formatvarargs(varargs))
-    if varkw:
+    if varkw is not None:
         specs.append(formatvarkw(varkw))
     return '(' + string.join(specs, ', ') + ')'