test/dropdown.py

import gradio as gr


def debug_click(drop_down):
    print(drop_down)
    return "yes"


with gr.Blocks() as demo:
    drop_down = gr.Dropdown(
        choices=["first", "second"], type="index", interactive=True, multiselect=False
    )
    txt = gr.Textbox()
    btn = gr.Button("Clear")
    btn.click(debug_click, inputs=drop_down, outputs=txt)