diff --git a/tools/toolchains/gcc.py b/tools/toolchains/gcc.py
index d05a2ea297..22c0e3c72c 100644
--- a/tools/toolchains/gcc.py
+++ b/tools/toolchains/gcc.py
@@ -22,7 +22,8 @@ from distutils.version import LooseVersion
 
 from tools.targets import CORE_ARCH
 from tools.toolchains.mbed_toolchain import mbedToolchain, TOOLCHAIN_PATHS
-from tools.utils import run_cmd, NotSupportedException
+from tools.utils import run_cmd
+
 
 class GCC(mbedToolchain):
     OFFICIALLY_SUPPORTED = True
@@ -37,15 +38,21 @@ class GCC(mbedToolchain):
 
     def __init__(self, target,  notify=None, macros=None, build_profile=None,
                  build_dir=None):
-        mbedToolchain.__init__(self, target, notify, macros,
-                               build_profile=build_profile, build_dir=build_dir)
+        mbedToolchain.__init__(
+            self,
+            target,
+            notify,
+            macros,
+            build_profile=build_profile,
+            build_dir=build_dir
+        )
 
-        tool_path=TOOLCHAIN_PATHS['GCC_ARM']
+        tool_path = TOOLCHAIN_PATHS['GCC_ARM']
         # Add flags for current size setting
         default_lib = "std"
         if hasattr(target, "default_lib"):
             default_lib = target.default_lib
-        elif hasattr(target, "default_build"): # Legacy
+        elif hasattr(target, "default_build"):
             default_lib = target.default_build
 
         if default_lib == "small":
@@ -109,8 +116,8 @@ class GCC(mbedToolchain):
         main_cc = join(tool_path, "arm-none-eabi-gcc")
         main_cppc = join(tool_path, "arm-none-eabi-g++")
         self.asm = [main_cc] + self.flags['asm'] + self.flags["common"]
-        self.cc  = [main_cc]
-        self.cppc =[main_cppc]
+        self.cc = [main_cc]
+        self.cppc = [main_cppc]
         self.cc += self.flags['c'] + self.flags['common']
         self.cppc += self.flags['cxx'] + self.flags['common']
 
@@ -129,9 +136,13 @@ class GCC(mbedToolchain):
         stdout, _, retcode = run_cmd([self.cc[0], "--version"], redirect=True)
         msg = None
         match = self.GCC_VERSION_RE.search(stdout.encode("utf-8"))
-        found_version = LooseVersion(match.group(0).decode('utf-8')) if match else None
+        if match:
+            found_version = LooseVersion(match.group(0).decode('utf-8'))
+        else:
+            found_version = None
         min_ver, max_ver = self.GCC_RANGE
-        if found_version and (found_version < min_ver or found_version >= max_ver):
+        if found_version and (found_version < min_ver
+                              or found_version >= max_ver):
             msg = ("Compiler version mismatch: Have {}; "
                    "expected version >= {} and < {}"
                    .format(found_version, min_ver, max_ver))
@@ -196,7 +207,9 @@ class GCC(mbedToolchain):
 
     def assemble(self, source, object, includes):
         # Build assemble command
-        cmd = self.asm + self.get_compile_options(self.get_symbols(True), includes) + ["-o", object, source]
+        cmd = self.asm + self.get_compile_options(
+            self.get_symbols(True), includes
+        ) + ["-o", object, source]
 
         # Return command array, don't execute
         return [cmd]
@@ -230,15 +243,23 @@ class GCC(mbedToolchain):
         # Preprocess
         if mem_map:
             preproc_output = join(dirname(output), ".link_script.ld")
-            cmd = (self.preproc + [mem_map] + self.ld[1:] +
-                   [ "-o", preproc_output])
+            cmd = (
+                self.preproc + [mem_map] + self.ld[1:] + ["-o", preproc_output]
+            )
             self.notify.cc_verbose("Preproc: %s" % ' '.join(cmd))
             self.default_cmd(cmd)
             mem_map = preproc_output
 
         # Build linker command
         map_file = splitext(output)[0] + ".map"
-        cmd = self.ld + ["-o", output, "-Wl,-Map=%s" % map_file] + objects + ["-Wl,--start-group"] + libs + ["-Wl,--end-group"]
+        cmd = (
+            self.ld +
+            ["-o", output, "-Wl,-Map=%s" % map_file] +
+            objects +
+            ["-Wl,--start-group"] +
+            libs +
+            ["-Wl,--end-group"]
+        )
 
         if mem_map:
             cmd.extend(['-T', mem_map])
@@ -291,9 +312,12 @@ class GCC(mbedToolchain):
     @staticmethod
     def check_executable():
         """Returns True if the executable (arm-none-eabi-gcc) location
-        specified by the user exists OR the executable can be found on the PATH.
-        Returns False otherwise."""
-        if not TOOLCHAIN_PATHS['GCC_ARM'] or not exists(TOOLCHAIN_PATHS['GCC_ARM']):
+        specified by the user exists OR the executable can be found on the
+        PATH. Returns False otherwise."""
+        if (
+            not TOOLCHAIN_PATHS['GCC_ARM'] or
+            not exists(TOOLCHAIN_PATHS['GCC_ARM'])
+        ):
             if find_executable('arm-none-eabi-gcc'):
                 TOOLCHAIN_PATHS['GCC_ARM'] = ''
                 return True
@@ -303,5 +327,6 @@ class GCC(mbedToolchain):
             exec_name = join(TOOLCHAIN_PATHS['GCC_ARM'], 'arm-none-eabi-gcc')
             return exists(exec_name) or exists(exec_name + '.exe')
 
+
 class GCC_ARM(GCC):
     pass