Example of using python AST module to produce some python code.

picci.py

import json
import ast
from ast import (
    ClassDef,
    FunctionDef,
    arguments,
    arg,
    BinOp,
    Name,
    Add,
    Sub,
    Load,
    Return,
)

# Read config
config = json.loads(
    """{
  "class": "FooBar",
  "methods": ["add", "sub"]
}"""
)

ops = {"add": ast.Add, "sub": ast.Sub}

# Create class
code = ClassDef(
    name=config["class"],
    bases=[],
    keywords=[],
    body=[
        FunctionDef(
            name=funz,
            args=arguments(
                posonlyargs=[],
                args=[arg(arg="self"), arg(arg="one"), arg(arg="two")],
                kwonlyargs=[],
                kw_defaults=[],
                defaults=[],
            ),
            body=[
                Return(
                    value=BinOp(
                        left=Name(id="one", ctx=Load()),
                        op=ops[funz](),
                        right=Name(id="two", ctx=Load()),
                    )
                )
            ],
            decorator_list=[],
        )
        for funz in config["methods"]
    ],
    decorator_list=[],
)

# Produce file (also count lines)
print(ast.unparse(ast.fix_missing_locations(code)))

# Santa's little exampler
# print(
#     ast.dump(
#         ast.parse(
#             """class FooBar:
#     def add(self, one, two):
#         return one + two
# """
#         ),
#         indent=4,
#     )
# )