import re


def parse_line(line):
    """
    Input: A string
    Output: One of 1. A dict with keys 'key', 'value'
                   2. 'nothing' (if the line contains no information)
                   2. 'unrecognized' (if parsing failed)
    """

    if re.match('\s*(#.*)?$', line):
        return 'nothing'

    match = re.match('\s*export\s+([^:\s]+)\s*:=\s*(.*)$', line)

    if match:
        return {
            'key': match.group(1),
            'value': match.group(2).strip()
        }
    else:
        return 'unrecognized'