How to use the aliyun-python-sdk-core-v3.aliyunsdkcore.auth.composer.roa_signature_composer.build_canonical_headers function in aliyun-python-sdk-core-v3

headers=None,
        paths=None,
        signer=mac1):
    sign_to_string = ""
    sign_to_string += method
    sign_to_string += HEADER_SEPARATOR
    if CONTENT_MD5 in headers and headers[CONTENT_MD5] is not None:
        sign_to_string += headers[CONTENT_MD5]
    sign_to_string += HEADER_SEPARATOR
    if CONTENT_TYPE in headers and headers[CONTENT_TYPE] is not None:
        sign_to_string += headers[CONTENT_TYPE]
    sign_to_string += HEADER_SEPARATOR
    if DATE in headers and headers[DATE] is not None:
        sign_to_string += headers[DATE]
    sign_to_string += HEADER_SEPARATOR
    sign_to_string += roa_signature_composer.build_canonical_headers(
        headers, "x-oss-")
    sign_to_string += __build_query_string(uri_pattern, queries)
    return sign_to_string