Regex help sos sos can not figure this one out for the life of me

import re

def getRegEx():
    regex = '([-+]*)([\d]*)([a-z]*)([=|<=|>=]*)'
    return regex

equation_1 = '3x<=6+2y+7z'
pattern = getRegEx()
print(re.findall(pattern, equation_1))
Actual result:
[('', '3', 'x', '<='), ('', '6', '', ''), ('+', '2', 'y', ''), ('+', '7', 'z', ''), ('', '', '', '')]

Expected result: 
[('', '3', 'x', '<='), ('', '6', '', ''), ('+', '2', 'y', ''), ('+', '7', 'z', '')]

I’m clearly matching the empty string but I can’t figure out how to stop it. Because certain sections I do need a 0 or more match.

If there is anyone that can help me I would really appreciate it. I’ve looked everywhere and can not figure this one out.