import re


def parse_extensions(extensions: str) -> re.Pattern:
    """
    Create a regex parser to check for file extensions.
        Note: Separate extensions by one of
            [',', '`', '*', ' ']
    """
    sep = [i for i in ',`* ' if i in extensions]
    pattern = '|'.join(f'\.{i}$' for i in extensions.split(sep[0] if sep else None))
    pat = re.compile(pattern, re.I)
    return pat