def validate_fluent_file(file_path):
    """Check if the fluent file has duplicate keys.
    Returns "fluent keys" in array.
    """
    print("\nValidating file:", file_path)
    fluent_keys = []
    with open(file_path, 'r') as file:
        for line in file.readlines():
            if line.find("=") != -1:
                translation_key = line.split("=")[0].strip()
                try:
                    fluent_keys.index(translation_key)
                    print(" - Duplicate [ " + translation_key +" ]. One of them can be removed.")
                except ValueError:
                    pass
                fluent_keys.append(translation_key)
    return fluent_keys