unlang code to unroll a list attribute

[Hermann.Lauer at uni-heidelberg.de]

Hello All,

how in unlang can a list attribute be converted into a string of the values,
eg. the DHCP-Parameter-Request-List into something like:
"DHCP-Subnet-Mask,DHCP-Router-Address,DHCP-Domain-Name-Server" ?

Thanks and greetings
  Hermann