def inner_mask_radii_tag_from_inner_circular_mask_radii(inner_mask_radii):
if inner_mask_radii == None:<EOL><INDENT>return '<STR_LIT>'<EOL><DEDENT>else:<EOL><INDENT>return '<STR_LIT>'.format(inner_mask_radii)<EOL><DEDENT>
Generate an inner mask radii tag, to customize phase names based on the size of the circular masked area in the \
    centre of an image.

    This changes the phase name 'phase_name' as follows:

    inner_circular_mask_radii = 1 -> phase_name
    inner_circular_mask_radii = 2 -> phase_name_inner_circular_mask_radii_2
    inner_circular_mask_radii = 2 -> phase_name_inner_circular_mask_radii_2