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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 _api_decrypt():
    '''
    Return the response dictionary from the KMS decrypt API call.
    '''
    kms = _kms()
    data_key = _cfg_data_key()
    try:
        return kms.decrypt(CiphertextBlob=data_key)
    except botocore.exceptions.ClientError as orig_exc:
        error_code = orig_exc.response.get('Error', {}).get('Code', '')
        if error_code != 'InvalidCiphertextException':
            raise
        err_msg = 'aws_kms:data_key is not a valid KMS data key'
        config_error = salt.exceptions.SaltConfigurationError(err_msg)
        six.raise_from(config_error, orig_exc)