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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_filekey(self):
 """This method creates a key from a keyfile."""


        if not os.path.exists(self.keyfile):
            raise KPError('Keyfile not exists.')
        try:
            with open(self.keyfile, 'rb') as handler:
                handler.seek(0, os.SEEK_END)
                size = handler.tell()
                handler.seek(0, os.SEEK_SET)

                if size == 32:
                    return handler.read(32)
                elif size == 64:
                    try:
                        return binascii.unhexlify(handler.read(64))
                    except (TypeError, binascii.Error):
                        handler.seek(0, os.SEEK_SET)

                sha = SHA256.new()
                while True:
                    buf = handler.read(2048)
                    sha.update(buf)
                    if len(buf) < 2048:
                        break
                return sha.digest()
        except IOError as e:
            raise KPError('Could not read file: %s' % e)