def METHOD_NAME(self, name, arches, paths):
    node = api.find_node(self.root, "project")
    existing = api.find_node(self.root, "project", "repository", {"name": name})
    if existing:
        raise oscerr.OscValueError(f"Repository '{name}' already exists in project meta")
    repo_node = ET.SubElement(node, "repository", attrib={"name": name})
    for path_data in paths:
        ET.SubElement(repo_node, "path", attrib={
            "project": path_data["project"],
            "repository": path_data["repository"],
        })
    for arch in arches:
        arch_node = ET.SubElement(repo_node, "arch")
        arch_node.text = arch
    api.group_child_nodes(repo_node)
    api.group_child_nodes(node)