String.join: def of Base
Import: import Base
Lines 2188-2193 of Base/base.bend: https://jend.leeeet.dev/read.txt?path=Base/base.bend&start_line=2188&end_line=2193

import Base

def String.join(xs: List<&2, String>, +sep: String) -> String:
  match xs:
    case Nil{}:
      SNil{}
    case h <> t:
      String.join.go(t, h, sep)

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=String.join.go