import traceback
import inspect
import sys

class MyError(Exception):
    def __init__(self, msg):
        super().__init__(msg)
        upstack, linenum = next(traceback.walk_stack(None))
        self.linenum = linenum
        self.traceback = upstack
        self.msg = msg
        args, _, _, values = inspect.getargvalues(upstack)
        self.func_args = {
            k:values[k] for k in args
        }

    def __str__(self):
        return """
        [ERROR] '{msg}'
        Occured at line: {linenum}
        In file: {filename}
        In function: {funcname} (starts at line {funcline})
        Called with args: {funcargs}
        """.format(
            msg=self.msg,
            linenum=self.linenum,
            filename=self.traceback.f_code.co_filename,
            funcname=self.traceback.f_code.co_name,
            funcline=self.traceback.f_code.co_firstlineno,
            funcargs=str(self.func_args)
        ).strip()

def foo(yay_arg, foo_arg):
    try:
        raise MyError("Helpful Error Message")
    except MyError as e:
        print(e)


if __name__ == "__main__":
    foo("one", foo_arg="bar")

>>>> [ERROR] 'Helpful Error Message'
>>>>    Occured at line: 35
>>>>    In file: custom_exceptions.py
>>>>    In function: foo (starts at line 33)
>>>>    Called with args: {'foo_arg': 'bar', 'yay_arg': 'one'}