docs: def deprecated(func):
      """This is a decorator which can be used to mark functions
      as deprecated. It will result in a warning being emitted
      when the function is used."""
  
      @functools.wraps(func)
      def decorated(*args, **kwargs):
          warnings.warn_explicit(
              "Call to deprecated function {}.".format(func.__name__),
              category=DeprecationWarning,
              filename=func.__code__.co_filename,
              lineno=func.__code__.co_firstlineno + 1
          )
  
          return func(*args, **kwargs)
      return decorated