Here are potential issues found in the `dataset_dict.py` file based on the provided hint:

<example>
{
    "issue": "Typographical error in the documentation",
    "evidence": "The type casting is applied to all the datasets of the dataset dictionary.",
    "description": "The sentence 'The type casting is applied to all the datasets of the dataset dictionary.' is not clear. It should be 'The type casting is applied to all datasets in the dataset dictionary.' for better readability."
},
{
    "issue": "Typographical error in function documentation",
    "evidence": "The function is applied on-the-fly on the examples when iterating over the dataset.",
    "description": "The sentence 'The function is applied on-the-fly on the examples when iterating over the dataset.' should be 'The function is applied on-the-fly to the examples when iterating over the dataset.' for better clarity."
}
</example>

These identified issues highlight typographical errors that can affect the readability and clarity of the documentation.