def check_sources_exist(self, subdir, sources):
    for s in sources:
        if (not isinstance(s, str)):
            continue
        fname = os.path.join(subdir, s)
        if (not os.path.isfile(fname)):
            raise InterpreterException(f'Tried to add non-existing source file {s}.')
def check_sources_exist(self, subdir, sources):
    for s in sources:
        if (not isinstance(s, str)):
            continue
        fname = os.path.join(subdir, s)
        if (not os.path.isfile(fname)):
            raise InterpreterException(f'Tried to add non-existing source file {s}.')