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.
    
    https://wiki.python.org/moin/PythonDecoratorLibrary#Generating_Deprecation_Warnings
    '''
    def new_func(*args, **kwargs):
        warn("Call to deprecated function {}.".format(func.__name__),
                      category=DeprecationWarning)
        return func(*args, **kwargs)
    new_func.__name__ = func.__name__
    new_func.__doc__ = func.__doc__
    new_func.__dict__.update(func.__dict__)
    return new_func