[ssci] PEP8 formatting for metadata directory

All files in metadata/ are new, so they should follow the PEP-8 style.

Change-Id: I5d8424536c3d7b703e6b8087e0e2d70c06a1549c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/4834909
Reviewed-by: Rachael Newitt <renewitt@google.com>
Commit-Queue: Rachael Newitt <renewitt@google.com>

metadata/discover.py

@@ -12,27 +12,27 @@ _METADATA_FILES = {
 
 
 def is_metadata_file(path: str) -> bool:
-  """Filter for metadata files."""
-  return os.path.basename(path) in _METADATA_FILES
+    """Filter for metadata files."""
+    return os.path.basename(path) in _METADATA_FILES
 
 
 def find_metadata_files(root: str) -> List[str]:
-  """Finds all metadata files within the given root directory, including
-  subdirectories.
+    """Finds all metadata files within the given root directory,
+    including subdirectories.
 
-  Args:
-    root: the absolute path to the root directory within which to search.
+    Args:
+      root: the absolute path to the root directory within which to
+            search.
 
-  Returns:
-    the absolute full paths for all the metadata files within the root
-    directory.
-  """
-  metadata_files = []
-  for item in os.listdir(root):
-    full_path = os.path.join(root, item)
-    if is_metadata_file(item):
-      metadata_files.append(full_path)
-    elif os.path.isdir(full_path):
-      metadata_files.extend(find_metadata_files(full_path))
+    Returns: the absolute full paths for all the metadata files within
+             the root directory.
+    """
+    metadata_files = []
+    for item in os.listdir(root):
+        full_path = os.path.join(root, item)
+        if is_metadata_file(item):
+            metadata_files.append(full_path)
+        elif os.path.isdir(full_path):
+            metadata_files.extend(find_metadata_files(full_path))
 
-  return metadata_files
+    return metadata_files