pureCoeIssue.lean:6:2: error: application type mismatch
  bind f1
argument
  f1
has type
  Nat → IO Unit
but is expected to have type
  IO PUnit
pureCoeIssue.lean:14:2: error: application type mismatch
  bind (f2 10)
argument
  f2 10
has type
  Nat → IO Unit
but is expected to have type
  IO PUnit