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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 get_template_path(filename):
 """Find raw template in working directory or in sys.path. template_path from config may refer to templates colocated with the Stacker config, or files in remote package_sources. Here, we emulate python module loading to find the path to the template. Args: filename (str):
 Template filename. Returns: Optional[str]: Path to file, or None if no file found """

    if os.path.isfile(filename):
        return os.path.abspath(filename)
    for i in sys.path:
        if os.path.isfile(os.path.join(i, filename)):
            return os.path.abspath(os.path.join(i, filename))

    return None