diff --git a/pre_commit/languages/all.py b/pre_commit/languages/all.py
index 4aa8787f..63c1d514 100644
--- a/pre_commit/languages/all.py
+++ b/pre_commit/languages/all.py
@@ -12,7 +12,11 @@ from pre_commit.languages import system
 # # Use None for no environment
 # ENVIRONMENT_DIR = 'foo_env'
 #
-# def install_environment(repo_cmd_runner, version='default'):
+# def install_environment(
+#         repo_cmd_runner,
+#         version='default',
+#         additional_dependencies=None,
+# ):
 #     """Installs a repository in the given repository.  Note that the current
 #     working directory will already be inside the repository.
 #
diff --git a/pre_commit/languages/node.py b/pre_commit/languages/node.py
index 129a1515..839daf00 100644
--- a/pre_commit/languages/node.py
+++ b/pre_commit/languages/node.py
@@ -24,9 +24,11 @@ def in_env(repo_cmd_runner, language_version):
     yield NodeEnv(repo_cmd_runner, language_version)
 
 
-def install_environment(repo_cmd_runner,
-                        version='default',
-                        additional_dependencies=None):
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=None,
+):
     assert repo_cmd_runner.exists('package.json')
     directory = helpers.environment_dir(ENVIRONMENT_DIR, version)
 
diff --git a/pre_commit/languages/pcre.py b/pre_commit/languages/pcre.py
index 4a7882c0..11d24eed 100644
--- a/pre_commit/languages/pcre.py
+++ b/pre_commit/languages/pcre.py
@@ -9,9 +9,11 @@ from pre_commit.util import shell_escape
 ENVIRONMENT_DIR = None
 
 
-def install_environment(repo_cmd_runner,
-                        version='default',
-                        additional_dependencies=None):
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=None,
+):
     """Installation for pcre type is a noop."""
     raise AssertionError('Cannot install pcre repo.')
 
diff --git a/pre_commit/languages/python.py b/pre_commit/languages/python.py
index 1acdcead..67e330e3 100644
--- a/pre_commit/languages/python.py
+++ b/pre_commit/languages/python.py
@@ -43,9 +43,11 @@ def norm_version(version):
     return version
 
 
-def install_environment(repo_cmd_runner,
-                        version='default',
-                        additional_dependencies=None):
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=None,
+):
     assert repo_cmd_runner.exists('setup.py')
     directory = helpers.environment_dir(ENVIRONMENT_DIR, version)
 
diff --git a/pre_commit/languages/ruby.py b/pre_commit/languages/ruby.py
index b80d8194..8d80d5b7 100644
--- a/pre_commit/languages/ruby.py
+++ b/pre_commit/languages/ruby.py
@@ -79,9 +79,11 @@ def _install_ruby(environment, version):
         environment.run('rbenv install {0}'.format(version))
 
 
-def install_environment(repo_cmd_runner,
-                        version='default',
-                        additional_dependencies=None):
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=None,
+):
     directory = helpers.environment_dir(ENVIRONMENT_DIR, version)
     with clean_path_on_failure(repo_cmd_runner.path(directory)):
         # TODO: this currently will fail if there's no version specified and
diff --git a/pre_commit/languages/script.py b/pre_commit/languages/script.py
index d6b25d05..cf2cee46 100644
--- a/pre_commit/languages/script.py
+++ b/pre_commit/languages/script.py
@@ -6,9 +6,11 @@ from pre_commit.languages.helpers import file_args_to_stdin
 ENVIRONMENT_DIR = None
 
 
-def install_environment(repo_cmd_runner,
-                        version='default',
-                        additional_dependencies=None):
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=None,
+):
     """Installation for script type is a noop."""
     raise AssertionError('Cannot install script repo.')
 
diff --git a/pre_commit/languages/system.py b/pre_commit/languages/system.py
index eec64ad3..3930422b 100644
--- a/pre_commit/languages/system.py
+++ b/pre_commit/languages/system.py
@@ -8,9 +8,11 @@ from pre_commit.languages.helpers import file_args_to_stdin
 ENVIRONMENT_DIR = None
 
 
-def install_environment(repo_cmd_runner,
-                        version='default',
-                        additional_dependencies=None):
+def install_environment(
+        repo_cmd_runner,
+        version='default',
+        additional_dependencies=None,
+):
     """Installation for system type is a noop."""
     raise AssertionError('Cannot install system repo.')