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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 _mergetree(src, dst):
    '''
    Akin to shutils.copytree but over existing directories, does a recursive merge copy.

    :param src: The source path
    :type  src: ``str``

    :param dst: The destination path
    :type  dst: ``str``
    '''
    for item in os.listdir(src):
        s = os.path.join(src, item)
        d = os.path.join(dst, item)
        if os.path.isdir(s):
            log.info("Copying folder %s to %s", s, d)
            if os.path.exists(d):
                _mergetree(s, d)
            else:
                shutil.copytree(s, d)
        else:
            log.info("Copying file %s to %s", s, d)
            shutil.copy2(s, d)