code: def get_address_host(addr: str) -> str:
      """
      Return a hostname / IP address identifying the machine this address
      is located on.
  
      In contrast to get_address_host_port(), this function should always
      succeed for well-formed addresses.
  
      >>> get_address_host('tcp://1.2.3.4:80')
      '1.2.3.4'
      """
      scheme, loc = parse_address(addr)
      backend = registry.get_backend(scheme)
      return backend.get_address_host(loc)
  
file_path: distributed/distributed/comm/addressing.py
imports: from __future__ import annotations
  import itertools
  import dask
  from distributed.comm import registry
  from distributed.utils import get_ip_interface
label_desc: Use image node_id 7 for calling a global function with example usage: get_address_host(addr) and returns: backend