Summing all FASTA headers

sum.py

"""
sum.py
"""

import sys

size = 0

def parse(line):
    if line[0] == ">":
        line = line[1:]

        result = {}

        for cell in line.split(";"):
            try:
                key, value = cell.split("=")
                result[key] = value
            except ValueError:
                result[cell] = None

    return result

for row in sys.stdin:
    result = parse(row)
    try:
        size += int(result["size"])
    except KeyError:
        pass

print(size)