code: def launch_instances(
      self,
      region_name: str,
      instance_type_name: str,
      ssh_key_names: List[str],
      file_system_names: List[str],
      quantity: int,
      name: Optional[str],
  ) -> List[str]:
      data = {
          "region_name": region_name,
          "instance_type_name": instance_type_name,
          "ssh_key_names": ssh_key_names,
          "file_system_names": file_system_names,
          "quantity": quantity,
          "name": name,
      }
      resp = self._make_request(
          "POST", "/instance-operations/launch", data
      )
      if resp.ok:
          return resp.json()["data"]["instance_ids"]
      resp.raise_for_status()
  
file_path: dstack/src/dstack/_internal/core/backends/lambdalabs/api_client.py
imports: from typing import Any, Dict, List, Optional
  import requests
label_desc: Use image node_id 5 for calling the LambdaAPIClient obj's underlying member method code with example usage: obj.launch_instances(region_name, instance_type_name, ssh_key_names, file_system_names, quantity, name) and returns: resp