data='''
abcd_Err: 0
ifgas_Err: 
higsi_Err: 0
'''
for line in data.splitlines():
    if '_Err' in line:
        key, value = line.split(':')
        print value

 0
 
 0

 0
 0
 0

 0
 
 0

abcd_Err:0

abcd_Err: 0

print value[1:]

print value.lstrip()

data='''
abcd_Err: 0
ifgas_hehe: 
ifgas_bzz: 
ifgas_Err: 
higsi_Err: 0
'''

import re

print re.findall(r'^\w+_Err:\s*(\d+)?$',data,re.MULTILINE)

['0', '', '0']