code: def toXML(self, writer, axisTags):
      writer.begintag("tuple")
      writer.newline()
      for axis in axisTags:
          value = self.axes.get(axis)
          if value is not None:
              minValue, value, maxValue = value
              defaultMinValue = min(
                  value, 0.0
              )  # -0.3 --> -0.3; 0.7 --> 0.0
              defaultMaxValue = max(
                  value, 0.0
              )  # -0.3 -->  0.0; 0.7 --> 0.7
              if (
                  minValue == defaultMinValue
                  and maxValue == defaultMaxValue
              ):
                  writer.simpletag(
                      "coord", axis=axis, value=fl2str(value, 14)
                  )
              else:
                  attrs = [
                      ("axis", axis),
                      ("min", fl2str(minValue, 14)),
                      ("value", fl2str(value, 14)),
                      ("max", fl2str(maxValue, 14)),
                  ]
                  writer.simpletag("coord", attrs)
              writer.newline()
      wrote_any_deltas = False
      for i, delta in enumerate(self.coordinates):
          if type(delta) == tuple and len(delta) == 2:
              writer.simpletag("delta", pt=i, x=delta[0], y=delta[1])
              writer.newline()
              wrote_any_deltas = True
          elif type(delta) == int:
              writer.simpletag("delta", cvt=i, value=delta)
              writer.newline()
              wrote_any_deltas = True
          elif delta is not None:
              log.error("bad delta format")
              writer.comment("bad delta #%d" % i)
              writer.newline()
              wrote_any_deltas = True
      if not wrote_any_deltas:
          writer.comment("no deltas")
          writer.newline()
      writer.endtag("tuple")
      writer.newline()
  
imports: from fontTools.misc.fixedTools import fixedToFloat, floatToFixed, floatToFixedToStr, strToFixedToFloat, otRound
  from fontTools.misc.textTools import safeEval
  import array
  from collections import Counter, defaultdict
  import io
  import logging
  import struct
  import sys
label_desc: Use image node_id 6 for calling the TupleVariation obj's underlying member method code with example usage: obj.toXML(writer, axisTags) without return types