def perform_smooth(x_values, y_values, span=None, smoother_cls=None):
if smoother_cls is None:<EOL><INDENT>smoother_cls = DEFAULT_BASIC_SMOOTHER<EOL><DEDENT>smoother = smoother_cls()<EOL>smoother.specify_data_set(x_values, y_values)<EOL>smoother.set_span(span)<EOL>smoother.compute()<EOL>return smoother<EOL>
Convenience function to run the basic smoother.

Parameters
----------
x_values : iterable
    List of x value observations
y_ values : iterable
    list of y value observations
span : float, optional
    Fraction of data to use as the window
smoother_cls : Class
    The class of smoother to use to smooth the data

Returns
-------
smoother : object
    The smoother object with results stored on it.