How to use the blimpy.io.sigproc function in blimpy

def __init__(self, filename=None, size_limit=SIZE_LIM, out_dir='./', n_coarse_chan=None, coarse_chans=None):
        """
        :param filename:        string,      name of file (.h5 or .fil)
        :param size_limit:      float,       maximum size in MB that the file is allowed to be
        :param out_dir:         string,      directory where output files should be saved
        """

        if filename and os.path.isfile(filename):
            self.filename = filename
            self.out_dir = out_dir
            self.n_coarse_chan = n_coarse_chan
            self.coarse_chans = coarse_chans

            if not h5py.is_hdf5(filename):
                if not sigproc.is_filterbank(filename):
                    raise IOError('No correct format, need .h5. Try again...')
                else:
                    logger.info("File .fil detected. Attempting to create .h5 file in current directory...")
                    try:
                        self.__make_h5_file()
                    except:
                        raise IOError('Unable to create .h5 file. Please, try again with correct format.')

            self.filestat = os.stat(filename)
            self.filesize = self.filestat.st_size/(1024.0**2)

            # Grab header from DATAH5
            dobj_master = DATAH5(filename)
            self.header = dobj_master.header
            dobj_master.close()