batch.spec

python = <<EOF

from batchutil import bazzinga

def foo():
    return f"foo: I am {self.name}"

def bar():
    return f"bar: I am {self.name}"
    
def baz():
    return bazzinga(self)
    
EOF

<batch>
  name p&l_calulator
  exec_str echo %foo()%
</batch>

batchutil.py

def bazzinga(batch):
    return f"baz: I am {batch.name}"

test.py

from apacheconfig import *
  
class BatchJobSpec:
    
    def __init__(self, pythoncode , batch):
        self.pythoncode = pythoncode
        self.name = batch.get("name")
        self._exec_str = batch.get("exec_str")
        self.exec()
    
    @property
    def exec_str(self):
        _exec = self._exec_str.split("%")
        
        for i in range(len(_exec)):
            if _exec[i].endswith('()'):
                f = self.__getattribute__(_exec[i][:-2])
                _exec[i] = f()
                return ''.join(_exec)
            
        
    def exec(self):
        locals_ = {'self': self}
        exec(self.pythoncode, locals_)
        
        _exec = []
        for attrib in locals_.keys():
            if not attrib in ['__builtins__', 'self']:
                print('__setattr__({})'.format(attrib))
                self.__setattr__(attrib, locals_[attrib])

with make_loader() as loader:
    config = loader.load('batch.spec')

batchjobspec = BatchJobSpec(config.get("python"), config.get("batch"))
print(batchjobspec.pythoncode)
print(batchjobspec.name)
print(batchjobspec.exec_str)
print(batchjobspec.baz())

I actually made it a staticmethod. Please review the code https://gist.github.com/agrawalo/407caf4dcd44687fae6989f46b54975a