how to get the value of a custom property if the name of the cProperty is in a variable?

[hh]

Two examples for testing ambiguity.

[a]
  set "8.1" of me to "I dreamt to be quoted"
  set 8.1 of me to "I dreamt to be 8.2"
  put the customProperties of me into cp
  put cp["8.1"] &" : "& cp[8.1] &" : "& cp[8+1/10]
Test and then interchange the first two lines and test again.

[b]
  set "G&T" of me to "I dreamt to be geometry and trigonometry"
  put the customProperties of me into cp
  put cp["G&T"]