code: def copy_keys(source, destination, keys=None):
      
      if keys is None:
          keys = destination.keys()
      for k in set(source) & set(keys):
          destination[k] = source[k]
      return destination
docs: Add keys in source to destination
  
      Parameters
      ----------
      source : dict
  
      destination: dict
  
      keys : None | iterable
          The keys in source to be copied into destination. If
          None, then `keys = destination.keys()`