text: import collections
  
  
  def deep_update(source, overrides):
      """Update a nested dictionary or similar mapping.
  
      Modify ``source`` in place.
      """
      for key, value in overrides.items():
          if isinstance(value, collections.Mapping) and value:
              returned = deep_update(source.get(key, {}), value)
              source[key] = returned
          else:
              source[key] = overrides[key]
      return source
  