The file Sample_Materials.xml that is accessed by the IronPython method update contains the MatML-formatted material data:

<?xml version="1.0" encoding="UTF-8"?>
<EngineeringData version="16.1">
  <Notes />
  <Materials>
    <MatML_Doc>
      <Material>
        <BulkDetails>
          <Name>Sample Material</Name>
          <Description>Sample material from Driver</Description>
          <PropertyData property="pr0">
            <Data format="string">-</Data>
            <ParameterValue parameter="pa0" format="float">
              <Data>494.1474492,912.7972764,1172.453938,1941.495468,2803.754154,3869.063522,5245.395513,
10378.82012,18192.58268,28438.67868,57755.1982,94951.87682,135751.6191,178064.7612,216504.4272,261538.9311,
304701.5076,333300.2826,364061.2544,397079.5705,432533.1159,457543.8578,483751.5301</Data>
              <Qualifier name="Variable Type">Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent,DependentDependent,Dependent,Dependent,Dependent,Dependent,Dependent,Dependent</Qualifier>
            </ParameterValue>
            <ParameterValue parameter="pa1" format="float">
              <Data>0.1338,0.2675,0.3567,0.6242,0.8917,1.1592,1.4268,2.051,2.586,3.0318,3.7898,4.3694,4.8153,5.172,5.4395,5.707,5.9299,6.0637,6.1975,6.3312,6.465,6.5541,6.6433</Data>
              <Qualifier name="Variable Type">Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent,Independent</Qualifier>
            </ParameterValue>
          </PropertyData>
          <PropertyData property="prDriver">
              <Data format="string">-</Data>
              <Qualifier name="Data Link Version">1</Qualifier>
              <Qualifier name="Model Type">Linear;Isotropic</Qualifier>
              <Qualifier name="Sample Property">Value</Qualifier>
          </PropertyData>
        </BulkDetails>
      </Material>
      <Metadata>
      <ParameterDetails id="pa0">
        <Name>Stress</Name>
        <Units>
          <Unit>
            <Name>Pa</Name>
          </Unit>
        </Units>
      </ParameterDetails>
      <ParameterDetails id="pa1">
        <Name>Strain</Name>
        <Units>
          <Unit>
            <Name>m</Name>
          </Unit>
          <Unit power="-1">
            <Name>m</Name>
          </Unit>
        </Units>
      </ParameterDetails>
      <PropertyDetails id="pr0">
        <Unitless />
        <Name>Sample Property</Name>
      </PropertyDetails>
      <PropertyDetails id="prDriver">
        <Unitless />
        <Name>Driver Link Details</Name>
      </PropertyDetails>
      </Metadata>
    </MatML_Doc>
  </Materials>
  <Loads />
  <BeamSections />
</EngineeringData>