[Python] Find pattern outside parentheses using regex in Python

Note: Many advance Regex functions are not available in several programming language as Python, Java 8, etc. Therefore, I included "in Python" that I'm using.

A topic from regex101 about "Conditional statement" in the "Group Constructs" section:

>>> re.search(r'(A candy)(?(1) is true| is false)', 'A candy is true')
<re.Match object; span=(0, 15), match='A candy is true'>
>>> re.search(r'(A candy)(?(1) is true| is false)', 'A candy is false')
( empty )
>>> re.search(r'(A candy)(?(1) is true| is false)', 'A candy is ok')
( empty )


And now I'm looking an expression to find the pattern i\d* or i([^()]+) but not enclosed in parentheses, for example

>>> re.search(r'(?(1)|[^(])(i([^a-z)]+|\([^()]+\))?)(?(1)|[^)])', 'helloi123bye')
<re.Match object; span=(4, 9), match='oi123'>
>>> re.search(r'(?(1)|[^(])(i([^a-z)]+|\([^()]+\))?)(?(1)|[^)])', 'helloi(123b)ye')
<re.Match object; span=(4, 12), match='oi(123b)'>
>>> re.search(r'(?(1)|[^(])(i([^a-z)]+|\([^()]+\))?)(?(1)|[^)])', 'hello(i123)bye')
( empty )
>>> re.search(r'(?(1)|[^(])(i([^a-z)]+|\([^()]+\))?)(?(1)|[^)])', 'hello(ai123)bye')
<re.Match object; span=(6, 11), match='ai123'>
>>> re.search(r'(?(1)|[^(])(i([^a-z)]+|\([^()]+\))?)(?(1)|[^)])', 'i123hellobye')
( empty )
>>> re.search(r'(?(1)|[^(])(i([^a-z)]+|\([^()]+\))?)(?(1)|[^)])', 'hellobyei123')
<re.Match object; span=(7, 12), match='ei123'>


There are several results that I don't want: First, including a, o or e before the pattern i\d* or i([^()]+); Second, the pattern i\d* (including a before it) is enclosed in parentheses; Third, i\d* was not found in the entire string i123hellobye.

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