def validate_multimodal_combination(field_content, is_non_tensor_field, field_mapping):
    """
    Validates the field content if it is a multimodal combination field (dict)
    Args:
        field_content: the field content
        is_non_tensor_field: whether this is a non-tensor-field
        field_mapping: the mapping to help validate this field content

    Returns:
        The field content
    """
    if len(field_content) < 1:
        raise InvalidArgError(
            f"The multimodal_combination field `{field_content}` is an empty dictionary."
            f"This is not a valid format of field content."
            f"If you aim to use multimodal_combination, it must contain at least 1 field. "
            f"please check `{marqo_docs.multimodal_combination_object()}` for more info.")

    for key, value in field_content.items():
        if not ((type(key) in tensor_search_constants.ALLOWED_MULTIMODAL_FIELD_TYPES) and (
                type(value) in tensor_search_constants.ALLOWED_MULTIMODAL_FIELD_TYPES)):
            raise InvalidArgError(
                f"Multimodal-combination field content `{key}:{value}` \n  "
                f"of type `{type(key).__name__} : {type(value).__name__}` is not of valid content type (one of {tensor_search_constants.ALLOWED_MULTIMODAL_FIELD_TYPES})."
            )

        if not key in field_mapping["weights"]:
            raise InvalidArgError(
                f"Multimodal-combination field content `{key}:{value}` \n  "
                f"is not in the multimodal_field mappings weights `{field_mapping['weights']}`. Each sub_field requires a weight."
                f"Please add `{key}` to the mappings."
                f"Please check `{marqo_docs.multimodal_combination_object()}` for more info.")

    if is_non_tensor_field:
        raise InvalidArgError(
            f"Field content `{field_content}` \n  "
            f"of type `{type(field_content).__name__}` is the content for a multimodal_combination."
            f"It must be a tensor field. Add this field to `tensorFields` or "
            f"add it as a normal field to fix this problem."
        )
    return field_content

    Validates the field content if it is a multimodal combination field (dict)
    Args:
        field_content: the field content
        is_non_tensor_field: whether this is a non-tensor-field
        field_mapping: the mapping to help validate this field content

    Returns:
        The field content
    
src/marqo/tensor_search/validation.py