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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 copy_file_if_modified(src_path, dest_path):
 """Only copies the file from the source path to the destination path if it doesn't exist yet or it has been modified. Intended to provide something of an optimisation when a project has large trees of assets."""


    # if the destination path is a directory, delete it completely - we assume here we are
    # writing a file to the filesystem
    if os.path.isdir(dest_path):
        shutil.rmtree(dest_path)

    must_copy = False
    if not os.path.exists(dest_path):
        must_copy = True
    else:
        src_stat = os.stat(src_path)
        dest_stat = os.stat(dest_path)

        # if the size or last modified timestamp are different
        if ((src_stat[stat.ST_SIZE] != dest_stat[stat.ST_SIZE]) or
                (src_stat[stat.ST_MTIME] != dest_stat[stat.ST_MTIME])):
            must_copy = True

    if must_copy:
        shutil.copy2(src_path, dest_path)