def create_rois_mask(roislist, filelist):
roifiles = []<EOL>for roi in roislist:<EOL><INDENT>try:<EOL><INDENT>roi_file = search_list(roi, filelist)[<NUM_LIT:0>]<EOL><DEDENT>except Exception as exc:<EOL><INDENT>raise Exception('<STR_LIT>'.format(str(exc)))<EOL><DEDENT>else:<EOL><INDENT>roifiles.append(roi_file)<EOL><DEDENT><DEDENT>return binarise(roifiles)<EOL>
Look for the files in filelist containing the names in roislist, these files will be opened, binarised
    and merged in one mask.

    Parameters
    ----------
    roislist: list of strings
        Names of the ROIs, which will have to be in the names of the files in filelist.

    filelist: list of strings
        List of paths to the volume files containing the ROIs.

    Returns
    -------
    numpy.ndarray
        Mask volume