import gzip


def verify_fq(filename):
	"""
	Return True if input is a valid fastQ file
	"""
	FQ = open(filename) if filename[-3:]!=".gz" else gzip.open(filename)
	l1 = FQ.readline()
	if l1[0]!="@":
		print("First character is not \"@\"\nPlease make sure this is fastq format\nExiting...")
		exit(1)
	else:
		return True