---input---
f'{fn(lst,2)} {fn(lst,3)}'

---tokens---
'f'           Literal.String.Affix
"'"           Literal.String.Single
'{'           Literal.String.Interpol
'fn'          Name
'('           Punctuation
'lst'         Name
','           Punctuation
'2'           Literal.Number.Integer
')'           Punctuation
'}'           Literal.String.Interpol
' '           Literal.String.Single
'{'           Literal.String.Interpol
'fn'          Name
'('           Punctuation
'lst'         Name
','           Punctuation
'3'           Literal.Number.Integer
')'           Punctuation
'}'           Literal.String.Interpol
"'"           Literal.String.Single
'\n'          Text.Whitespace