diff --git a/scripts/sysmon/git_metrics.py b/scripts/sysmon/git_metrics.py
index 06a411f..8b034e2 100644
--- a/scripts/sysmon/git_metrics.py
+++ b/scripts/sysmon/git_metrics.py
@@ -17,114 +17,124 @@
 
 
 class _GitRepo(object):
-  """Helper class for running git commands."""
+    """Helper class for running git commands."""
 
-  def __init__(self, gitdir):
-    self._gitdir = gitdir
+    def __init__(self, gitdir):
+        self._gitdir = gitdir
 
-  def _get_git_command(self):
-    return ['git', '--git-dir', self._gitdir]
+    def _get_git_command(self):
+        return ["git", "--git-dir", self._gitdir]
 
-  def _check_output(self, args, **kwargs):
-    return subprocess.check_output(
-        self._get_git_command() + list(args), **kwargs).decode('utf-8')
+    def _check_output(self, args, **kwargs):
+        return subprocess.check_output(
+            self._get_git_command() + list(args), **kwargs
+        ).decode("utf-8")
 
-  def get_commit_hash(self):
-    """Return commit hash string."""
-    return self._check_output(['rev-parse', 'HEAD']).strip()
+    def get_commit_hash(self):
+        """Return commit hash string."""
+        return self._check_output(["rev-parse", "HEAD"]).strip()
 
-  def get_commit_time(self):
-    """Return commit time as UNIX timestamp int."""
-    return int(self._check_output(['show', '-s', '--format=%ct', 'HEAD'])
-               .strip())
+    def get_commit_time(self):
+        """Return commit time as UNIX timestamp int."""
+        return int(
+            self._check_output(["show", "-s", "--format=%ct", "HEAD"]).strip()
+        )
 
-  def get_unstaged_changes(self):
-    """Return number of unstaged changes as (added, deleted)."""
-    added_total, deleted_total = 0, 0
-    # output looks like:
-    # '1\t2\tfoo\n3\t4\tbar\n'
-    # '-\t-\tbinary_file\n'
-    output = self._check_output(['diff-index', '--numstat', 'HEAD'])
-    stats_strings = (line.split() for line in output.splitlines())
-    for added, deleted, _path in stats_strings:
-      if added != '-':
-        added_total += int(added)
-      if deleted != '-':
-        deleted_total += int(deleted)
-    return added_total, deleted_total
+    def get_unstaged_changes(self):
+        """Return number of unstaged changes as (added, deleted)."""
+        added_total, deleted_total = 0, 0
+        # output looks like:
+        # '1\t2\tfoo\n3\t4\tbar\n'
+        # '-\t-\tbinary_file\n'
+        output = self._check_output(["diff-index", "--numstat", "HEAD"])
+        stats_strings = (line.split() for line in output.splitlines())
+        for added, deleted, _path in stats_strings:
+            if added != "-":
+                added_total += int(added)
+            if deleted != "-":
+                deleted_total += int(deleted)
+        return added_total, deleted_total
 
 
 class _GitMetricCollector(object):
-  """Class for collecting metrics about a git repository.
+    """Class for collecting metrics about a git repository.
 
-  The constructor takes the arguments: `gitdir`, `metric_path`.
-  `gitdir` is the path to the Git directory to collect metrics for and
-  may start with a tilde (expanded to a user's home directory).
-  `metric_path` is the Monarch metric path to report to.
-  """
+    The constructor takes the arguments: `gitdir`, `metric_path`.
+    `gitdir` is the path to the Git directory to collect metrics for and
+    may start with a tilde (expanded to a user's home directory).
+    `metric_path` is the Monarch metric path to report to.
+    """
 
-  _commit_hash_metric = metrics.StringMetric(
-      'git/hash',
-      description='Current Git commit hash.')
+    _commit_hash_metric = metrics.StringMetric(
+        "git/hash", description="Current Git commit hash."
+    )
 
-  _timestamp_metric = metrics.GaugeMetric(
-      'git/timestamp',
-      description='Current Git commit time as seconds since Unix Epoch.')
+    _timestamp_metric = metrics.GaugeMetric(
+        "git/timestamp",
+        description="Current Git commit time as seconds since Unix Epoch.",
+    )
 
-  _unstaged_changes_metric = metrics.GaugeMetric(
-      'git/unstaged_changes',
-      description='Unstaged Git changes.')
+    _unstaged_changes_metric = metrics.GaugeMetric(
+        "git/unstaged_changes", description="Unstaged Git changes."
+    )
 
-  def __init__(self, gitdir, metric_path):
-    self._gitdir = gitdir
-    self._gitrepo = _GitRepo(os.path.expanduser(gitdir))
-    self._fields = {'repo': gitdir}
-    self._metric_path = metric_path
+    def __init__(self, gitdir, metric_path):
+        self._gitdir = gitdir
+        self._gitrepo = _GitRepo(os.path.expanduser(gitdir))
+        self._fields = {"repo": gitdir}
+        self._metric_path = metric_path
 
-  def collect(self):
-    """Collect metrics."""
-    try:
-      self._collect_commit_hash_metric()
-      self._collect_timestamp_metric()
-      self._collect_unstaged_changes_metric()
-    except subprocess.CalledProcessError as e:
-      logger.warning(u'Error collecting git metrics for %s: %s',
-                     self._gitdir, e)
+    def collect(self):
+        """Collect metrics."""
+        try:
+            self._collect_commit_hash_metric()
+            self._collect_timestamp_metric()
+            self._collect_unstaged_changes_metric()
+        except subprocess.CalledProcessError as e:
+            logger.warning(
+                "Error collecting git metrics for %s: %s", self._gitdir, e
+            )
 
-  def _collect_commit_hash_metric(self):
-    commit_hash = self._gitrepo.get_commit_hash()
-    logger.debug(u'Collecting Git hash %r for %r', commit_hash, self._gitdir)
-    self._commit_hash_metric.set(commit_hash, self._fields)
+    def _collect_commit_hash_metric(self):
+        commit_hash = self._gitrepo.get_commit_hash()
+        logger.debug("Collecting Git hash %r for %r", commit_hash, self._gitdir)
+        self._commit_hash_metric.set(commit_hash, self._fields)
 
-  def _collect_timestamp_metric(self):
-    commit_time = self._gitrepo.get_commit_time()
-    logger.debug(u'Collecting Git timestamp %r for %r',
-                 commit_time, self._gitdir)
-    self._timestamp_metric.set(commit_time, self._fields)
+    def _collect_timestamp_metric(self):
+        commit_time = self._gitrepo.get_commit_time()
+        logger.debug(
+            "Collecting Git timestamp %r for %r", commit_time, self._gitdir
+        )
+        self._timestamp_metric.set(commit_time, self._fields)
 
-  def _collect_unstaged_changes_metric(self):
-    added, deleted = self._gitrepo.get_unstaged_changes()
-    self._unstaged_changes_metric.set(
-        added, fields=dict(change_type='added', **self._fields))
-    self._unstaged_changes_metric.set(
-        deleted, fields=dict(change_type='deleted', **self._fields))
+    def _collect_unstaged_changes_metric(self):
+        added, deleted = self._gitrepo.get_unstaged_changes()
+        self._unstaged_changes_metric.set(
+            added, fields=dict(change_type="added", **self._fields)
+        )
+        self._unstaged_changes_metric.set(
+            deleted, fields=dict(change_type="deleted", **self._fields)
+        )
 
 
-_CHROMIUMOS_DIR = '~chromeos-test/chromiumos/'
+_CHROMIUMOS_DIR = "~chromeos-test/chromiumos/"
 
 _repo_collectors = (
     # TODO(ayatane): We cannot access chromeos-admin because we are
     # running as non-root.
-    _GitMetricCollector(gitdir='/root/chromeos-admin/.git',
-                        metric_path='chromeos-admin'),
-    _GitMetricCollector(gitdir=_CHROMIUMOS_DIR + 'chromite/.git',
-                        metric_path='chromite'),
-    _GitMetricCollector(gitdir='/usr/local/autotest/.git',
-                        metric_path='installed_autotest'),
+    _GitMetricCollector(
+        gitdir="/root/chromeos-admin/.git", metric_path="chromeos-admin"
+    ),
+    _GitMetricCollector(
+        gitdir=_CHROMIUMOS_DIR + "chromite/.git", metric_path="chromite"
+    ),
+    _GitMetricCollector(
+        gitdir="/usr/local/autotest/.git", metric_path="installed_autotest"
+    ),
 )
 
 
 def collect_git_metrics():
-  """Collect metrics for Git repository state."""
-  for collector in _repo_collectors:
-    collector.collect()
+    """Collect metrics for Git repository state."""
+    for collector in _repo_collectors:
+        collector.collect()