code: def fromXML(self, name, attrs, content, ttFont):
      self.ulFormat = safeEval(attrs["format"])
      self.usReserved1 = safeEval(attrs.get("reserved1", "0"))
      self.usReserved2 = safeEval(attrs.get("reserved2", "0"))
      self.pkcs7 = base64.b64decode(
          tobytes(strjoin(filter(pem_spam, content)))
      )
  
file_path: catboost/contrib/python/fonttools/fontTools/ttLib/tables/D_S_I_G_.py
imports: from fontTools.misc.textTools import bytesjoin, strjoin, tobytes, tostr, safeEval
  from fontTools.misc import sstruct
  from .None import DefaultTable
  import base64
label_desc: Use image node_id 3 for calling the SignatureRecord obj's underlying member method code with example usage: obj.fromXML(name, attrs, content, ttFont) without return types