Is your feature request related to a problem? Please describe.
Currently, source_code in Submisson only accepts str. When attempting to use Executable by uploading bytes, it is blocked by pydantic validation. This limitation causes issues for scenarios where bytes are required.

Describe the solution you'd like
Allow source_code in Submisson to also accept bytes in addition to str. Modifying the field definition to source_code: Optional[str] = Field(default=None, repr=True) seems to resolve the issue and enable the desired functionality.