code: def fromXML(self, name, attrs, content, ttFont):
      metricNames = set(sstruct.getformat(sbitLineMetricsFormat)[1])
      for element in content:
          if not isinstance(element, tuple):
              continue
          name, attrs, content = element
          if name in metricNames:
              vars(self)[name] = safeEval(attrs["value"])
  
imports: from fontTools.misc import sstruct
  from .None import DefaultTable
  from fontTools.misc.textTools import bytesjoin, safeEval
  from .BitmapGlyphMetrics import BigGlyphMetrics, bigGlyphMetricsFormat, SmallGlyphMetrics, smallGlyphMetricsFormat
  import struct
  import itertools
  from collections import deque
  import logging
label_desc: Use image node_id 2 for calling the SbitLineMetrics obj's underlying member method code with example usage: obj.fromXML(name, attrs, content, ttFont) without return types