=System.IO.File.ReadAllText("C:SomeDirectorySomeFile.xml")

<PermissionSet class="NamedPermissionSet" version="1" Name="MyPermissionSet" Description="REMOVE ME!!!">
    <IPermission class="FileIOPermission" version="1" />
</PermissionSet>

<CodeGroup class="UnionCodeGroup" version="1" PermissionSetName="MyPermissionSet" Name="Report_Expressions_Default_Permissions" Description="This code group grants default permissions for code in report expressions and Code element. ">
          <IMembershipCondition class="StrongNameMembershipCondition" version="1" PublicKeyBlob="..." />