How to use the stix2.Relationship function in stix2

bundle_objects.append(relationship_indicator_URLS)

    if len(pattern_ip) != 0:
        stix2_ip = "".join(pattern_ip)
        stix2_ip = stix2_ip[:-4]

        indicator_IPS = stix2.Indicator(
            name=TITLE + " - IPS",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_ip,
            object_marking_refs=[marking_def_white]
        )
        relationship_indicator_IPS = stix2.Relationship(indicator_IPS, "indicates", campaign_MAIN)
        bundle_objects.append(indicator_IPS)
        bundle_objects.append(relationship_indicator_IPS)

    if len(pattern_email) != 0:
        stix2_email = "".join(pattern_email)
        stix2_email = stix2_email[:-4]

        indicator_EMAILS = stix2.Indicator(
            name=TITLE + " - EMAILS",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_email,
            object_marking_refs=[marking_def_white]
        )

bundle_objects = [campaign_MAIN, marking_def_white]

    if len(pattern_sha256) != 0:
        stix2_sha256 = "".join(pattern_sha256)
        stix2_sha256 = stix2_sha256[:-4]

        indicator_SHA256 = stix2.Indicator(
            name=TITLE + " - SHA256",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_sha256,
            object_marking_refs=[marking_def_white]
        )
        relationship_indicator_SHA256 = stix2.Relationship(indicator_SHA256, "indicates", campaign_MAIN)
        bundle_objects.append(indicator_SHA256)
        bundle_objects.append(relationship_indicator_SHA256)

    if len(pattern_md5) != 0:
        stix2_md5 = "".join(pattern_md5)
        stix2_md5 = stix2_md5[:-4]

        indicator_MD5 = stix2.Indicator(
            name=TITLE + " - MD5",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_md5,
            object_marking_refs=[marking_def_white]
        )

bundle_objects.append(relationship_indicator_IPS)

    if len(pattern_email) != 0:
        stix2_email = "".join(pattern_email)
        stix2_email = stix2_email[:-4]

        indicator_EMAILS = stix2.Indicator(
            name=TITLE + " - EMAILS",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_email,
            object_marking_refs=[marking_def_white]
        )
        relationship_indicator_EMAILS = stix2.Relationship(indicator_EMAILS, "indicates", campaign_MAIN)
        bundle_objects.append(indicator_EMAILS)
        bundle_objects.append(relationship_indicator_EMAILS)

    # creo il bunble STIX 2
    bundlestix2 = stix2.Bundle(objects=bundle_objects)

    if (ioccount > 0):
        ########################
        # save to STIX 1.2 file
        print("Writing STIX 1.2 package: " + OUTFILEPREFIX + ".stix")
        f = open(OUTFILEPREFIX + ".stix", "wb")
        f.write(wrapper.to_xml())
        f.close()

        ########################
        # save to STIX 2 file

bundle_objects.append(relationship_indicator_DOMAINS)

    if len(pattern_url) != 0:
        stix2_url = "".join(pattern_url)
        stix2_url = stix2_url[:-4]

        indicator_URLS = stix2.Indicator(
            name=TITLE + " - URL",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_url,
            object_marking_refs=[marking_def_white]
        )
        relationship_indicator_URLS = stix2.Relationship(indicator_URLS, "indicates", campaign_MAIN)
        bundle_objects.append(indicator_URLS)
        bundle_objects.append(relationship_indicator_URLS)

    if len(pattern_ip) != 0:
        stix2_ip = "".join(pattern_ip)
        stix2_ip = stix2_ip[:-4]

        indicator_IPS = stix2.Indicator(
            name=TITLE + " - IPS",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_ip,
            object_marking_refs=[marking_def_white]
        )

bundle_objects.append(relationship_indicator_SHA256)

    if len(pattern_md5) != 0:
        stix2_md5 = "".join(pattern_md5)
        stix2_md5 = stix2_md5[:-4]

        indicator_MD5 = stix2.Indicator(
            name=TITLE + " - MD5",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_md5,
            object_marking_refs=[marking_def_white]
        )
        relationship_indicator_MD5 = stix2.Relationship(indicator_MD5, "indicates", campaign_MAIN)
        bundle_objects.append(indicator_MD5)
        bundle_objects.append(relationship_indicator_MD5)

    if len(pattern_sha1) != 0:
        stix2_sha1 = "".join(pattern_sha1)
        stix2_sha1 = stix2_sha1[:-4]

        indicator_SHA1 = stix2.Indicator(
            name=TITLE + " - SHA1",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_sha1,
            object_marking_refs=[marking_def_white]
        )

bundle_objects.append(relationship_indicator_MD5)

    if len(pattern_sha1) != 0:
        stix2_sha1 = "".join(pattern_sha1)
        stix2_sha1 = stix2_sha1[:-4]

        indicator_SHA1 = stix2.Indicator(
            name=TITLE + " - SHA1",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_sha1,
            object_marking_refs=[marking_def_white]
        )
        relationship_indicator_SHA1 = stix2.Relationship(indicator_SHA1, "indicates", campaign_MAIN)
        bundle_objects.append(indicator_SHA1)
        bundle_objects.append(relationship_indicator_SHA1)

    if len(pattern_domain) != 0:
        stix2_domain = "".join(pattern_domain)
        stix2_domain = stix2_domain[:-4]

        indicator_DOMAINS = stix2.Indicator(
            name=TITLE + " - DOMAINS",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_domain,
            object_marking_refs=[marking_def_white]
        )

bundle_objects.append(relationship_indicator_SHA1)

    if len(pattern_domain) != 0:
        stix2_domain = "".join(pattern_domain)
        stix2_domain = stix2_domain[:-4]

        indicator_DOMAINS = stix2.Indicator(
            name=TITLE + " - DOMAINS",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_domain,
            object_marking_refs=[marking_def_white]
        )
        relationship_indicator_DOMAINS = stix2.Relationship(indicator_DOMAINS, "indicates", campaign_MAIN)
        bundle_objects.append(indicator_DOMAINS)
        bundle_objects.append(relationship_indicator_DOMAINS)

    if len(pattern_url) != 0:
        stix2_url = "".join(pattern_url)
        stix2_url = stix2_url[:-4]

        indicator_URLS = stix2.Indicator(
            name=TITLE + " - URL",
            created=timestamp,
            modified=timestamp,
            description=DESCRIPTION,
            labels=["malicious-activity"],
            pattern=stix2_url,
            object_marking_refs=[marking_def_white]
        )