<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def parse_line(string):
 """Parse a single string as traceback line"""

    match = line_regexp().match(string)
    if match:
        matches = match.groupdict()
        line_number = matches['line_number']
        path_to_python = matches['path_to_python']
        spaceless_path_to_python = matches['spaceless_path_to_python']
        if path_to_python:
            return path_to_python, line_number
        elif spaceless_path_to_python:
            return spaceless_path_to_python, line_number