Bulk change spacing of all glyphs in RoboFont

ChangeMetrics

class ChangeMetrics:
    
    def __init__(self):
        for currentGlyph in CurrentFont():
          left_space    = currentGlyph.leftMargin
          right_space   = currentGlyph.rightMargin

          # Define the value by which you want to change the metrics.
          change_units_by = 5

          currentGlyph.leftMargin  += change_units_by
          currentGlyph.rightMargin += change_units_by

          print "Spacing successfully changed unit of %s by %s" % (currentGlyph.name, change_units_by)

ChangeMetrics()