pureCoeIssue.lean:7:2-7:4: error: Type mismatch
  f1
has type
  Nat → IO Unit
but is expected to have type
  IO Unit
pureCoeIssue.lean:15:2-15:7: error: Type mismatch
  f2 10
has type
  Nat → IO Unit
but is expected to have type
  IO Unit