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diff --git a/tools/private/update_deps/update_file.py b/tools/private/update_deps/update_file.py
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+++ b/tools/private/update_deps/update_file.py
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+# Copyright 2023 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""A small library to update bazel files within the repo.
+
+This is reused in other files updating coverage deps and pip deps.
+"""
+
+import argparse
+import difflib
+import pathlib
+import sys
+
+
+def _writelines(path: pathlib.Path, out: str):
+    with open(path, "w") as f:
+        f.write(out)
+
+
+def unified_diff(name: str, a: str, b: str) -> str:
+    return "".join(
+        difflib.unified_diff(
+            a.splitlines(keepends=True),
+            b.splitlines(keepends=True),
+            fromfile=f"a/{name}",
+            tofile=f"b/{name}",
+        )
+    ).strip()
+
+
+def replace_snippet(
+    current: str,
+    snippet: str,
+    start_marker: str,
+    end_marker: str,
+) -> str:
+    """Update a file on disk to replace text in a file between two markers.
+
+    Args:
+        path: pathlib.Path, the path to the file to be modified.
+        snippet: str, the snippet of code to insert between the markers.
+        start_marker: str, the text that marks the start of the region to be replaced.
+        end_markr: str, the text that marks the end of the region to be replaced.
+        dry_run: bool, if set to True, then the file will not be written and instead we are going to print a diff to
+            stdout.
+    """
+    lines = []
+    skip = False
+    found_match = False
+    for line in current.splitlines(keepends=True):
+        if line.lstrip().startswith(start_marker.lstrip()):
+            found_match = True
+            lines.append(line)
+            lines.append(snippet.rstrip() + "\n")
+            skip = True
+        elif skip and line.lstrip().startswith(end_marker):
+            skip = False
+            lines.append(line)
+            continue
+        elif not skip:
+            lines.append(line)
+
+    if not found_match:
+        raise RuntimeError(f"Start marker '{start_marker}' was not found")
+    if skip:
+        raise RuntimeError(f"End marker '{end_marker}' was not found")
+
+    return "".join(lines)
+
+
+def update_file(
+    path: pathlib.Path,
+    snippet: str,
+    start_marker: str,
+    end_marker: str,
+    dry_run: bool = True,
+):
+    """update a file on disk to replace text in a file between two markers.
+
+    Args:
+        path: pathlib.Path, the path to the file to be modified.
+        snippet: str, the snippet of code to insert between the markers.
+        start_marker: str, the text that marks the start of the region to be replaced.
+        end_markr: str, the text that marks the end of the region to be replaced.
+        dry_run: bool, if set to True, then the file will not be written and instead we are going to print a diff to
+            stdout.
+    """
+    current = path.read_text()
+    out = replace_snippet(current, snippet, start_marker, end_marker)
+
+    if not dry_run:
+        _writelines(path, out)
+        return
+
+    relative = path.relative_to(
+        pathlib.Path(__file__).resolve().parent.parent.parent.parent
+    )
+    name = f"{relative}"
+    diff = unified_diff(name, current, out)
+    if diff:
+        print(f"Diff of the changes that would be made to '{name}':\n{diff}")
+    else:
+        print(f"'{name}' is up to date")