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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def find_config(revision):
 """Locate and return the default config for current revison."""

    if not is_git_repo():
        return None

    cfg_path = f"{revision}:.cherry_picker.toml"
    cmd = "git", "cat-file", "-t", cfg_path

    try:
        output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
        path_type = output.strip().decode("utf-8")
        return cfg_path if path_type == "blob" else None
    except subprocess.CalledProcessError:
        return None