human
I wrote the below code

    if (predicate is None):
        predicate = (lambda line: line.strip())
    def prefixed_lines():
        for line in text.splitlines(True):
            (yield ((prefix + line) if predicate(line) else line))
    return ''.join(prefixed_lines())

What's a good function header?
 ... What is a Python code to fix + line) if predicate(line) else line))?
assistant
#Here is Python code to fix + line) if predicate(line) else line))
.

def _indent(text, prefix, predicate=None):