def _isQualityHead(line):
if len(line) < <NUM_LIT:1>:<EOL><INDENT>return False<EOL><DEDENT>if line[<NUM_LIT:0>] == '<STR_LIT:+>':<EOL><INDENT>return True<EOL><DEDENT>return False<EOL>
Determine whether a string represents a quality header in fastq format.
Quality headers begin with the '+' symbol; subsequent line(s) will be
quality data.

:return: True if <line> is the header line of a fastq quality sequence