app.py

import gradio as gr
import pymorphy3

morph = pymorphy3.MorphAnalyzer()
morph = pymorphy3.MorphAnalyzer(lang='ru')

def infinitive(text):
    words = text.split()
    newstr = ""
    for word in words:
        p = morph.parse(str(word))[0]
        newstr += f"{p.normal_form} "
    return newstr

iface = gr.Interface(fn=infinitive, inputs="text", outputs="text")
iface.launch()