def ashraeiam(self, aoi):
        """
        Determine the incidence angle modifier using
        ``self.module_parameters['b']``, ``aoi``,
        and the :py:func:`ashraeiam` function.

        Uses default arguments if keys not in module_parameters.

        Parameters
        ----------
        aoi : numeric
            The angle of incidence in degrees.

        Returns
        -------
        modifier : numeric
            The AOI modifier.
        """
        kwargs = _build_kwargs(['b'], self.module_parameters)

        return ashraeiam(aoi, **kwargs)