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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_sha256_digest(self, content):
 """Return the sha256 digest of the content in the header format the Merchant API expects. """

        content_sha256 = base64.b64encode(SHA256.new(content).digest())
        return 'SHA256=' + content_sha256