The ambiguity in the style of writing a function should not be confused with a multivalued function, which can (and should) be defined in a deterministic and unambiguous way.
ðɪ ˌæmbɪɡjˈuːɪɾi ɪnðə stˈaɪl ʌv ɹˈaɪɾɪŋ ɐ fˈʌŋkʃən ʃˌʊd nˌɑːt biː kənfjˈuːzd wɪð ɐ mˌʌltɪvˈæljuːd fˈʌŋkʃən, wˌɪtʃ kæn ænd ʃˌʊd biː dᵻfˈaɪnd ɪn ɐ dɪtˌɜːmɪnˈɪstɪk ænd ʌnæmbˈɪɡjuːəs wˈeɪ.