A shortcut to create Lambdas?

Hey, I love toolz, but the one thin I've been missing is a possibility to create lambdas in a less verbose way.
At some point I had installed a library (which I can't seem to find anymore) that created lambdas through the use of _. Eg _ == x was translated to: lambda x: x == 3 but it had it's limits as something like len(_) would not work.

I wrote a function that takes a string, replaces percent signs by arguments and evals it:

import re

def _f_single_arg(function):
    body = (function.replace('%%', '<!>')
                    .replace('%', '_0')
                    .replace('<!>', '%'))
    return eval('lambda _0: ' + body)

def f(function):
    """Translates the provided expression in string form into a lambda. 
    Any %<n> where <n> is a int will be used as nth
    argument (starting with 0). If only one argument is required,
    a % can be used. To escape a % sign use %%."""
    single_percent_match = re.search(r"%[^\d]|%$", function)
    if single_percent_match:
        return _f_single_arg(function)
    
    matches = re.findall(r"%(?P<n>\d+)", function)
    n_args = 0 if len(matches) == 0 else\
        max(int(match) for match in matches) + 1
    replace_tuples = [(f'%{n}', f'_{n}') for n in range(n_args)]
    new_body = function
    # Not very functional, but since this is python
    # I think it's pragmatic
    for tup in replace_tuples:
        new_body = new_body.replace(*tup)
    head = 'lambda ' + ', '.join(pluck(1, replace_tuples)) + ': ' \
        if n_args > 0 else 'lambda *_0: '
    return eval(head + new_body)

Trying it out:

>>> f("%1")(0, "Hey")
"Hey"

>>> f('%')('Hey')
"Hey"

>>> f('"Hey"')(0, 1, 2)
"Hey"

I found this would fit one of my favorite libraries perfectly, what do you think about this?

No target files or tests are named. Start by reviewing the proposed string-to-lambda behavior in issue #461, including its percent-argument examples and eval-based implementation, then confirm the feature scope and safety expectations with maintainers; done means an agreed design and tests for the documented examples.