diff --git a/lib/ansible/modules/system/known_hosts.py b/lib/ansible/modules/system/known_hosts.py
index b03f4ed472a..9784d0354e3 100644
--- a/lib/ansible/modules/system/known_hosts.py
+++ b/lib/ansible/modules/system/known_hosts.py
@@ -102,69 +102,68 @@ def enforce_state(module, params):
     """
 
     host = params["name"]
-    key = params.get("key",None)
-    port = params.get("port",None)
+    key = params.get("key", None)
+    port = params.get("port", None)
     path = params.get("path")
     hash_host = params.get("hash_host")
     state = params.get("state")
-    #Find the ssh-keygen binary
-    sshkeygen = module.get_bin_path("ssh-keygen",True)
+    # Find the ssh-keygen binary
+    sshkeygen = module.get_bin_path("ssh-keygen", True)
 
     # Trailing newline in files gets lost, so re-add if necessary
     if key and key[-1] != '\n':
-        key+='\n'
+        key += '\n'
 
     if key is None and state != "absent":
         module.fail_json(msg="No key specified when adding a host")
 
-    sanity_check(module,host,key,sshkeygen)
+    sanity_check(module, host, key, sshkeygen)
 
-    found,replace_or_add,found_line,key=search_for_host_key(module,host,key,hash_host,path,sshkeygen)
+    found, replace_or_add, found_line, key = search_for_host_key(module, host, key, hash_host, path, sshkeygen)
 
     params['diff'] = compute_diff(path, found_line, replace_or_add, state, key)
 
-    #We will change state if found==True & state!="present"
-    #or found==False & state=="present"
-    #i.e found XOR (state=="present")
-    #Alternatively, if replace is true (i.e. key present, and we must change it)
+    # We will change state if found==True & state!="present"
+    # or found==False & state=="present"
+    # i.e found XOR (state=="present")
+    # Alternatively, if replace is true (i.e. key present, and we must change
+    # it)
     if module.check_mode:
-        module.exit_json(changed = replace_or_add or (state=="present") != found,
+        module.exit_json(changed=replace_or_add or (state == "present") != found,
                          diff=params['diff'])
 
-    #Now do the work.
+    # Now do the work.
 
-    #Only remove whole host if found and no key provided
-    if found and key is None and state=="absent":
-        module.run_command([sshkeygen,'-R',host,'-f',path], check_rc=True)
+    # Only remove whole host if found and no key provided
+    if found and key is None and state == "absent":
+        module.run_command([sshkeygen, '-R', host, '-f', path], check_rc=True)
         params['changed'] = True
 
-    #Next, add a new (or replacing) entry
-    if replace_or_add or found != (state=="present"):
+    # Next, add a new (or replacing) entry
+    if replace_or_add or found != (state == "present"):
         try:
-            inf=open(path,"r")
+            inf = open(path, "r")
         except IOError:
             e = get_exception()
             if e.errno == errno.ENOENT:
-                inf=None
+                inf = None
             else:
-                module.fail_json(msg="Failed to read %s: %s" % \
-                                     (path,str(e)))
+                module.fail_json(msg="Failed to read %s: %s" % (path, str(e)))
         try:
             outf = tempfile.NamedTemporaryFile(mode='w+', dir=os.path.dirname(path))
             if inf is not None:
                 for line_number, line in enumerate(inf):
-                    if found_line==(line_number + 1) and (replace_or_add or state=='absent'):
-                        continue # skip this line to replace its key
+                    if found_line == (line_number + 1) and (replace_or_add or state == 'absent'):
+                        continue  # skip this line to replace its key
                     outf.write(line)
                 inf.close()
             if state == 'present':
                 outf.write(key)
             outf.flush()
-            module.atomic_move(outf.name,path)
-        except (IOError,OSError):
+            module.atomic_move(outf.name, path)
+        except (IOError, OSError):
             e = get_exception()
-            module.fail_json(msg="Failed to write to file %s: %s" % \
-                                 (path,str(e)))
+            module.fail_json(msg="Failed to write to file %s: %s" % (path, str(e)))
 
         try:
             outf.close()
@@ -175,7 +174,8 @@ def enforce_state(module, params):
 
     return params
 
-def sanity_check(module,host,key,sshkeygen):
+
+def sanity_check(module, host, key, sshkeygen):
     '''Check supplied key is sensible
 
     host and key are parameters provided by the user; If the host
@@ -183,26 +183,26 @@ def sanity_check(module,host,key,sshkeygen):
     quits, providing an error to the user.
     sshkeygen is the path to ssh-keygen, found earlier with get_bin_path
     '''
-    #If no key supplied, we're doing a removal, and have nothing to check here.
+    # If no key supplied, we're doing a removal, and have nothing to check here.
     if key is None:
         return
-    #Rather than parsing the key ourselves, get ssh-keygen to do it
-    #(this is essential for hashed keys, but otherwise useful, as the
-    #key question is whether ssh-keygen thinks the key matches the host).
+    # Rather than parsing the key ourselves, get ssh-keygen to do it
+    # (this is essential for hashed keys, but otherwise useful, as the
+    # key question is whether ssh-keygen thinks the key matches the host).
 
-    #The approach is to write the key to a temporary file,
-    #and then attempt to look up the specified host in that file.
+    # The approach is to write the key to a temporary file,
+    # and then attempt to look up the specified host in that file.
     try:
         outf = tempfile.NamedTemporaryFile(mode='w+')
         outf.write(key)
         outf.flush()
     except IOError:
         e = get_exception()
-        module.fail_json(msg="Failed to write to temporary file %s: %s" % \
-                             (outf.name,str(e)))
-    rc,stdout,stderr=module.run_command([sshkeygen,'-F',host,
-                                         '-f',outf.name],
-                                        check_rc=True)
+        module.fail_json(msg="Failed to write to temporary file %s: %s" %
+                             (outf.name, str(e)))
+
+    sshkeygen_command = [sshkeygen, '-F', host, '-f', outf.name]
+    rc, stdout, stderr = module.run_command(sshkeygen_command, check_rc=True)
     try:
         outf.close()
     except:
@@ -211,6 +211,7 @@ def sanity_check(module,host,key,sshkeygen):
     if stdout == '':  # host not found
         module.fail_json(msg="Host parameter does not match hashed host field in supplied key")
 
+
 def search_for_host_key(module, host, key, hash_host, path, sshkeygen):
     '''search_for_host_key(module,host,key,path,sshkeygen) -> (found,replace_or_add,found_line)
 
@@ -225,16 +226,15 @@ def search_for_host_key(module, host, key, hash_host, path, sshkeygen):
     if os.path.exists(path) is False:
         return False, False, None, key
 
-    sshkeygen_command=[sshkeygen, '-F', host, '-f', path]
+    sshkeygen_command = [sshkeygen, '-F', host, '-f', path]
 
     # openssh >=6.4 has changed ssh-keygen behaviour such that it returns
     # 1 if no host is found, whereas previously it returned 0
-    rc,stdout,stderr=module.run_command(sshkeygen_command,
-                                        check_rc = False)
+    rc, stdout, stderr = module.run_command(sshkeygen_command, check_rc=False)
     if stdout == '' and stderr == '' and (rc == 0 or rc == 1):
         return False, False, None, key  # host not found, no other errors
     if rc != 0:  # something went wrong
-        module.fail_json(msg="ssh-keygen failed (rc=%d,stdout='%s',stderr='%s')" % (rc,stdout,stderr))
+        module.fail_json(msg="ssh-keygen failed (rc=%d, stdout='%s',stderr='%s')" % (rc, stdout, stderr))
 
     # If user supplied no key, we don't want to try and replace anything with it
     if key is None:
@@ -246,7 +246,7 @@ def search_for_host_key(module, host, key, hash_host, path, sshkeygen):
     sshkeygen_command.insert(1, '-H')
     rc, stdout, stderr = module.run_command(sshkeygen_command, check_rc=False)
     if rc not in (0, 1) or stderr != '':  # something went wrong
-        module.fail_json(msg="ssh-keygen failed to hash host (rc=%d,stdout='%s',stderr='%s')" % (rc, stdout, stderr))
+        module.fail_json(msg="ssh-keygen failed to hash host (rc=%d, stdout='%s',stderr='%s')" % (rc, stdout, stderr))
     hashed_lines = stdout.split('\n')
 
     for lnum, l in enumerate(lines):
@@ -263,18 +263,19 @@ def search_for_host_key(module, host, key, hash_host, path, sshkeygen):
             found_key = normalize_known_hosts_key(l)
             if hash_host is True:
                 if found_key['host'][:3] == '|1|':
-                    new_key['host']=found_key['host']
+                    new_key['host'] = found_key['host']
                 else:
-                    hashed_host=normalize_known_hosts_key(hashed_lines[lnum])
-                    found_key['host']=hashed_host['host']
-                key=key.replace(host,found_key['host'])
-            if new_key==found_key:  # found a match
+                    hashed_host = normalize_known_hosts_key(hashed_lines[lnum])
+                    found_key['host'] = hashed_host['host']
+                key = key.replace(host, found_key['host'])
+            if new_key == found_key:  # found a match
                 return True, False, found_line, key  # found exactly the same key, don't replace
             elif new_key['type'] == found_key['type']:  # found a different key for the same key type
                 return True, True, found_line, key
     # No match found, return found and replace, but no line
     return True, True, None, key
 
+
 def normalize_known_hosts_key(key):
     '''
     Transform a key, either taken from a known_host file or provided by the
@@ -284,21 +285,22 @@ def normalize_known_hosts_key(key):
     from the end (like the username@host tag usually present in hostkeys, but
     absent in known_hosts files)
     '''
-    k=key.strip() #trim trailing newline
-    k=key.split()
+    k = key.strip()  # trim trailing newline
+    k = key.split()
     d = dict()
-    #The optional "marker" field, used for @cert-authority or @revoked
+    # The optional "marker" field, used for @cert-authority or @revoked
     if k[0][0] == '@':
         d['options'] = k[0]
-        d['host']=k[1]
-        d['type']=k[2]
-        d['key']=k[3]
+        d['host'] = k[1]
+        d['type'] = k[2]
+        d['key'] = k[3]
     else:
-        d['host']=k[0]
-        d['type']=k[1]
-        d['key']=k[2]
+        d['host'] = k[0]
+        d['type'] = k[1]
+        d['key'] = k[2]
     return d
 
+
 def compute_diff(path, found_line, replace_or_add, state, key):
     diff = {
         'before_header': path,
@@ -323,20 +325,21 @@ def compute_diff(path, found_line, replace_or_add, state, key):
     diff['after'] = ''.join(lines)
     return diff
 
+
 def main():
 
     module = AnsibleModule(
-        argument_spec = dict(
-            name      = dict(required=True,  type='str', aliases=['host']),
-            key       = dict(required=False,  type='str'),
-            path      = dict(default="~/.ssh/known_hosts", type='path'),
-            hash_host = dict(required=False, type='bool' ,default=False),
-            state     = dict(default='present', choices=['absent','present']),
-            ),
-        supports_check_mode = True
-        )
+        argument_spec=dict(
+            name=dict(required=True, type='str', aliases=['host']),
+            key=dict(required=False, type='str'),
+            path=dict(default="~/.ssh/known_hosts", type='path'),
+            hash_host=dict(required=False, type='bool', default=False),
+            state=dict(default='present', choices=['absent', 'present']),
+        ),
+        supports_check_mode=True
+    )
 
-    results = enforce_state(module,module.params)
+    results = enforce_state(module, module.params)
     module.exit_json(**results)
 
 if __name__ == '__main__':
diff --git a/test/sanity/pep8/legacy-files.txt b/test/sanity/pep8/legacy-files.txt
index 6d533c740f9..36ce76ccff6 100644
--- a/test/sanity/pep8/legacy-files.txt
+++ b/test/sanity/pep8/legacy-files.txt
@@ -729,7 +729,6 @@ lib/ansible/modules/system/hostname.py
 lib/ansible/modules/system/iptables.py
 lib/ansible/modules/system/java_cert.py
 lib/ansible/modules/system/kernel_blacklist.py
-lib/ansible/modules/system/known_hosts.py
 lib/ansible/modules/system/locale_gen.py
 lib/ansible/modules/system/lvg.py
 lib/ansible/modules/system/lvol.py