Regular expression parsing with groups. Why does final output contain extra tuple

Question

Hello I am attempting to parse a sting with regular expression groups. The final output looks good but has an extra tuple in the list that is empty. How can I fix this. I don't understand why it is happening.

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', '')]

This question is not similar to a preciously asked question. I have multiple. If I replace any of the current * with plus's I will not get the required output.

*

Because the pattern matches the empty string too (also, `[=|<=|>=]*` is not how you use a character set, alternate with `|` only *outside* a character set) — CertainPerformance, Feb 17 '19 at 23:52
okay so your saying it should look like this ([=]*|[<=]*|[>=]*)? — Kevin Ayers, Feb 17 '19 at 23:57
No, character sets don't make any sense there, just use ordinary alternation — CertainPerformance, Feb 17 '19 at 23:58
ugh I'm still having some trouble is there anyway you could show me an example of how it should be done. I guess I don't understand. — Kevin Ayers, Feb 18 '19 at 00:02
I'm not sure what you're intending to do with the `*`s there, are you expecting inputs like `3x<=>=` or something? Looks like you want `?` instead — CertainPerformance, Feb 18 '19 at 00:03
You can turn that character class into a group using `(?:...)`: `([=|<=|>=]*)` => `((?:[<>]?=)*)`. Not sure it is what you really want, but that is what should work. Still you will need to avoid matching an empty string, add `(?=.)` or `(?!$)` at the start. — Wiktor Stribiżew, Feb 18 '19 at 00:04
the sucker still matches an empty group. This is a tough one :( — Kevin Ayers, Feb 18 '19 at 00:13
No, there are only [4 matches](https://regex101.com/r/e4iljf/1). See [my answer](https://stackoverflow.com/a/50188154/3832970) with at least 2 solutions for your case. — Wiktor Stribiżew, Feb 18 '19 at 00:22

Regular expression parsing with groups. Why does final output contain extra tuple

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