def get_parts(pair, default=None):
    """pair is expected to be a string with some key, value, and this function
       will replace any "=" with a space, and then parse the remainder
       for a first and second part (key and value pair). 

       We likely will need to use regular expressions for pairs that have 
       spaces or equals that need to be maintained.

       Parameters
       ==========
       pair should be a single string, likely with a key and value split by 
            a space or equals sign.

    """
    pair = pair.replace('=', ' ')
    parts = pair.split(' ')
    src = parts[0].strip()
    if len(parts) == 1:
        dest = default
    else:
        dest = parts[1].strip()
    return src, dest
