实现传感器读数单位自动转换

def solve():
    from pyodide.http import open_url
    from io import StringIO
    import pandas as pd
    st_csv = open_url(____).read()
    st = pd.read_csv(StringIO(____))
    def convert_unit(____):
        if from_unit in (____):
            return round((____)*____/____, ____), '____'
        if from_unit == '____':
            return round(____), '____'
        if from_unit == '____':
            return round(____), '____'
        return value, from_unit
    test_cases = [
        (____, '____', '____'),
        (____, '____', '____'),
        (____, '____', '____'),
        (____, '____', '____'),
    ]
    print(____)
    for val, unit, metric in test_cases:
        converted, new_unit = convert_unit(____)
        print("____" + str(____) + "____" + unit + "____" + str(____) + "____" + new_unit)