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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 open(cls, dbfile, encoding=None, fieldnames_lower=True, case_sensitive=True):
 """Context manager. Allows opening a .dbf file. .. code-block:: with Dbf.open('some.dbf') as dbf: :param str|unicode|file dbfile: .dbf filepath or a file-like object. :param str|unicode encoding: Encoding used by DB. This will be used if there's no encoding information in the DB itself. :param bool fieldnames_lower: Lowercase field names. :param bool case_sensitive: Whether DB filename is case sensitive. :rtype: Dbf """

        if not case_sensitive:
            if isinstance(dbfile, string_types):
                dbfile = pick_name(dbfile, listdir(path.dirname(dbfile)))

        with open(dbfile, 'rb') as f:
            yield cls(f, encoding=encoding, fieldnames_lower=fieldnames_lower)