Relation rst#cause (pm#description_content/medium/container,pm#description_content/medium/container)  not a subtype of pm#cause since pm#cause connects situations
  exclusion:  rst#circumstance  rst#solution  rst#elaboration  rst#effect  rst#definition  rst#comparison  rst#means  rst#condition  rst#otherwise  rst#interpretation  rst#restatement  rst#summary  rst#theme  rst#contrast
  supertype:  rst#subject_matter_rhetorical_relation  connect to details for making a better description
  subtype:  rst#volitional_cause (pm#description_content/medium/container,pm#description_content/medium/container)  cause of the described intended situation
  subtype:  rst#non-volitional_cause (pm#description_content/medium/container,pm#description_content/medium/container)  cause of the described not intended situation
  subtype:  rst#purpose (pm#description_content/medium/container,pm#description_content/medium/container)  situation that the described action is intended to reach