<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def from_argparse(cls, opts):
 """ Initialize an instance of the ethincaParameters class from an argparse.OptionParser instance. This assumes that insert_ethinca_metric_options and verify_ethinca_metric_options have already been called before initializing the class. """

        return cls(opts.ethinca_pn_order, opts.filter_cutoff,
            opts.ethinca_frequency_step, fLow=None,
            full_ethinca=opts.calculate_ethinca_metric,
            time_ethinca=opts.calculate_time_metric_components)