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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 _set_file_encoding_utf8(filename):
 """set a encoding header as suggested in PEP-0263. This is not entirely correct because we don't know the encoding of the given file but it's at least a chance to get metadata from the setup.py"""

    with open(filename, 'r+') as f:
        content = f.read()
        f.seek(0, 0)
        f.write("# -*- coding: utf-8 -*-\n" + content)