import os

class Config:
    def __init__(self, filename):
        self.filename = filename
        self.variables = {}
        if os.path.isfile(filename):
            f = open(filename, 'r')
            exec(f.read(), self.variables)

    def write(self):
        f = open(self.filename, 'w')
        for var in self.variables:
            if var[0] != '_':
                f.write("%s = %s\n" % (var, repr(self.variables[var])))
        f.close()

    def get(self, var):
        return self.variables[var] if var in self.variables else None

    def set(self, var, val):
        self.variables[var] = val