import pandas as pd
import streamlit as st

def load_uploaded_file(uploaded_file) -> pd.DataFrame | None:
    filename = uploaded_file.name.lower()

    if filename.endswith(".csv"):
        return pd.read_csv(uploaded_file)
    elif filename.endswith(".parquet"):
        return pd.read_parquet(uploaded_file)
    else:
        st.error("Unsupported file type. Please upload a CSV or Parquet file.")
        return