import re


def find_coords_string(file_path):
    """
    Parse a file path using a regular expresion to find a substring
    that looks like a set of coordinates,
    and return that.
    """

    match = re.search(
        "([-]?[\d]{1,3}\.[\d]{1,3}[_,][-]?[\d]{1,3}\.[\d]{1,3})", file_path
    )
    if not match:
        return None
    coords_string = match.groups()[0]
    return coords_string