ERROR: CSV parse error on line 2

KeyError: 'my_key'

def file_encoding(filepath):
    '''
    Text encoding is a bit of a schmozzle in Python. Alas.
    
    A quick summary:
    
    1. I come across CSV files with a UTF-8 or UTF-16 encoding regularly enough.
    2. Python wants to know the encoding when we open the file
    3. UTF-16 is fine, but UTF-8 comes in two flavours, with and without a BOM
    4. The BOM (byte order mark) is an optional and irrelevant to UTF-8 field
    5. In fact Unicode standards recommend against including a BOM with UTF-8
        https://en.wikipedia.org/wiki/Byte_order_mark#UTF-8
    6. Python assumes it's not there
    7. Some CSV sources though write with a BOM
    8. The encoding must therefore be specified as:
        utf-16     for UTF-16 files
        utf-8       for UTF-8 files with no BOM
        utf-8-sig for UTF files with a BOM 
    9. The "magic" library reliably determines the encoding efficiently by looking
       at the magic numbers at the start of a file
    10. Alas it returns a rich string describing the encoding.
    11. It contains either UTF-16 or UTF-18
    12. It contains "(with BOM)" if a BOM is detected
    13. Because of this schmozzle a quick function to translate "magic" output
        to standard encoding names is here.
    
    :param filepath: The path to a file
    '''
    m = magic.from_file(filepath)
    utf16 = m.find("UTF-16")>=0
    utf8 = m.find("UTF-8")>=0
    bom = m.find("(with BOM)")>=0
    
    if utf16:
        return "utf-16"
    elif utf8:
        if bom:
            return "utf-8-sig"
        else:
            return "utf-8"

with open(File1, "r", encoding=file_encoding(File1), newline='') as f1:
    csv1 = load_csv(f1, key=key)
    
with open(File2, "r", encoding=file_encoding(File2), newline='') as f2:
    csv2 = load_csv(f2, key=key)

diff = compare(csv1, csv2)