def METHOD_NAME(ciphertext, project_id, loc, env, secret_name):
    """
    Decrypt the ciphertext by using the GCloud KMS keys for that secret.
    """
    kms_client = kms.KeyManagementServiceClient()
    key_path = kms_client.crypto_key_path(project_id, loc, env, secret_name)
    # Optional, but recommended: compute ciphertext's CRC32C.
    # See crc32c() function defined below.
    ciphertext_crc32c = crc32c(ciphertext)
    response = kms_client.decrypt(
        request={'name': key_path, 'ciphertext': ciphertext, 'ciphertext_crc32c': ciphertext_crc32c})
    # Optional, but recommended: perform integrity verification on decrypt_response.
    # For more details on ensuring E2E in-transit integrity to and from Cloud KMS visit:
    # https://cloud.google.com/kms/docs/data-integrity-guidelines
    if not response.plaintext_crc32c == crc32c(response.plaintext):
        raise Exception('The response received from the server was corrupted in-transit.')
    return response.plaintext