def _line_format(line):
for pat in (FOUR_COL_REGEX, THREE_COL_REGEX, TWO_COL_REGEX):<EOL><INDENT>if pat.match(line):<EOL><INDENT>return pat<EOL><DEDENT><DEDENT>raise ValueError("<STR_LIT>".format(line))<EOL>
Determine the column format pattern for a line in an ASCII segment file.