diff --git a/contrib/linearize/linearize-data.py b/contrib/linearize/linearize-data.py
--- a/contrib/linearize/linearize-data.py
+++ b/contrib/linearize/linearize-data.py
@@ -156,7 +156,8 @@
 
         (blkDate, blkTS) = get_blk_dt(blk_hdr)
         if self.timestampSplit and (blkDate > self.lastDate):
-            print("New month " + blkDate.strftime("%Y-%m") + " @ " + self.hash_str)
+            print("New month " + blkDate.strftime("%Y-%m") +
+                  " @ " + self.hash_str)
             self.lastDate = blkDate
             if self.outF:
                 self.outF.close()
diff --git a/test/functional/p2p_invalid_locator.py b/test/functional/p2p_invalid_locator.py
--- a/test/functional/p2p_invalid_locator.py
+++ b/test/functional/p2p_invalid_locator.py
@@ -46,7 +46,7 @@
             msg.locator.vHave = [int(node.getblockhash(
                 i - 1), 16) for i in range(block_count, block_count - (MAX_LOCATOR_SZ), -1)]
             node.p2p.send_message(msg)
-            if type(msg) == msg_getheaders:
+            if isinstance(msg, msg_getheaders):
                 node.p2p.wait_for_header(int(node.getbestblockhash(), 16))
             else:
                 node.p2p.wait_for_block(int(node.getbestblockhash(), 16))
diff --git a/test/functional/test_framework/address.py b/test/functional/test_framework/address.py
--- a/test/functional/test_framework/address.py
+++ b/test/functional/test_framework/address.py
@@ -51,16 +51,16 @@
 
 
 def check_key(key):
-    if (type(key) is str):
+    if (isinstance(key, str)):
         key = hex_str_to_bytes(key)  # Assuming this is hex string
-    if (type(key) is bytes and (len(key) == 33 or len(key) == 65)):
+    if (isinstance(key, bytes) and (len(key) == 33 or len(key) == 65)):
         return key
     assert False
 
 
 def check_script(script):
-    if (type(script) is str):
+    if (isinstance(script, str)):
         script = hex_str_to_bytes(script)  # Assuming this is hex string
-    if (type(script) is bytes or type(script) is CScript):
+    if (isinstance(script, bytes) or isinstance(script, CScript)):
         return script
     assert False
diff --git a/test/functional/wallet_groups.py b/test/functional/wallet_groups.py
--- a/test/functional/wallet_groups.py
+++ b/test/functional/wallet_groups.py
@@ -56,8 +56,7 @@
         assert_equal(1, len(tx1["vin"]))
         assert_equal(2, len(tx1["vout"]))
         # one output should be 0.2, the other should be ~0.3
-        v = [vout["value"] for vout in tx1["vout"]]
-        v.sort()
+        v = sorted([vout["value"] for vout in tx1["vout"]])
         assert_approx(v[0], 0.2)
         assert_approx(v[1], 0.3, 0.0001)
 
@@ -67,8 +66,7 @@
         assert_equal(2, len(tx2["vin"]))
         assert_equal(2, len(tx2["vout"]))
         # one output should be 0.2, the other should be ~1.3
-        v = [vout["value"] for vout in tx2["vout"]]
-        v.sort()
+        v = sorted([vout["value"] for vout in tx2["vout"]])
         assert_approx(v[0], 0.2)
         assert_approx(v[1], 1.3, 0.0001)
 
diff --git a/test/lint/lint-format-strings.py b/test/lint/lint-format-strings.py
--- a/test/lint/lint-format-strings.py
+++ b/test/lint/lint-format-strings.py
@@ -59,8 +59,8 @@
     >>> len(parse_function_calls("foo", "#define FOO foo();"))
     0
     """
-    assert type(function_name) is str and type(
-        source_code) is str and function_name
+    assert isinstance(function_name, str) and isinstance(
+        source_code, str) and function_name
     lines = [re.sub("// .*", " ", line).strip()
              for line in source_code.split("\n")
              if not line.strip().startswith("#")]
@@ -74,7 +74,7 @@
     >>> normalize("  /* nothing */   foo\tfoo  /* bar */  foo     ")
     'foo foo foo'
     """
-    assert type(s) is str
+    assert isinstance(s, str)
     s = s.replace("\n", " ")
     s = s.replace("\t", " ")
     s = re.sub(r"/\*.*?\*/", " ", s)
@@ -98,7 +98,7 @@
     >>> escape(r'foo \\t foo \\n foo \\\\ foo \\ foo \\"bar\\"')
     'foo [escaped-tab] foo [escaped-newline] foo \\\\\\\\ foo \\\\ foo [escaped-quote]bar[escaped-quote]'
     """
-    assert type(s) is str
+    assert isinstance(s, str)
     for raw_value, escaped_value in ESCAPE_MAP.items():
         s = s.replace(raw_value, escaped_value)
     return s
@@ -113,7 +113,7 @@
     >>> unescape("foo [escaped-tab] foo [escaped-newline] foo \\\\\\\\ foo \\\\ foo [escaped-quote]bar[escaped-quote]")
     'foo \\\\t foo \\\\n foo \\\\\\\\ foo \\\\ foo \\\\"bar\\\\"'
     """
-    assert type(s) is str
+    assert isinstance(s, str)
     for raw_value, escaped_value in ESCAPE_MAP.items():
         s = s.replace(escaped_value, raw_value)
     return s
@@ -146,8 +146,8 @@
     >>> parse_function_call_and_arguments("foo", 'foo("foo")')
     ['foo(', '"foo"', ')']
     """
-    assert type(function_name) is str and type(
-        function_call) is str and function_name
+    assert isinstance(function_name, str) and isinstance(
+        function_call, str) and function_name
     remaining = normalize(escape(function_call))
     expected_function_call = "{}(".format(function_name)
     assert remaining.startswith(expected_function_call)
@@ -199,7 +199,7 @@
     >>> parse_string_content('1 2 3')
     ''
     """
-    assert type(argument) is str
+    assert isinstance(argument, str)
     string_content = ""
     in_string = False
     for char in normalize(escape(argument)):
@@ -226,7 +226,7 @@
     >>> count_format_specifiers("foo %d bar %i foo %% foo %*d foo")
     4
     """
-    assert type(format_string) is str
+    assert isinstance(format_string, str)
     n = 0
     in_specifier = False
     for i, char in enumerate(format_string):