def next_line(grd_file):
	"""
	next_line
	Function returns the next line in the file
	that is not a blank line, unless the line is
	'', which is a typical EOF marker.
	"""

	done   = False
	while not done:
		line = grd_file.readline()
		if line == '':
			return line, False
		elif line.strip():
			return line, True