espnet3.contract.data.check_fields

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espnet3.contract.data.check_fields(obj, attr: str) → Tuple[Field, ...] | None

Return obj.<attr> if well-formed, or None if undeclared.

A dataset’s fields is one standalone tuple: a tuple of Field, non-empty, with distinct names. None lets a caller decide whether an undeclared attr is allowed, or not (call require_fields()).

• Parameters:
  • obj – The class to check, or an instance whose own attributes (set in its __init__) declare a contract its class does not.
  • attr – The attribute name, such as "fields".
• Returns: The declared fields, or None when obj does not declare attr.
• Raises:TypeError – obj.<attr> is declared but malformed.

Examples

>>> class Good:
...     fields = (Field("speech", "audio"), Field("text", "text"))
>>> check_fields(Good, "fields")[0].name
'speech'
>>> class Bad:
...     fields = (Field("text", "text"), Field("text", "text"))
>>> check_fields(Bad, "fields")
Traceback (most recent call last):
TypeError: Bad.fields repeats a name: ['text', 'text']