astropy.io.fits.hdu.base:_ValidHDU.req_cards

Parameters

keyword : str

The keyword to validate

pos : int, callable

If an int, this specifies the exact location this card should have in the header. Remember that Python is zero-indexed, so this means pos=0 requires the card to be the first card in the header. If given a callable, it should take one argument--the actual position of the keyword--and return True or False. This can be used for custom evaluation. For example if pos=lambda idx: idx > 10 this will check that the keyword's index is greater than 10.

test : callable

This should be a callable (generally a function) that is passed the value of the given keyword and returns True or False. This can be used to validate the value associated with the given keyword.

fix_value : str, int, float, complex, bool, None

A valid value for a FITS keyword to use if the given test fails to replace an invalid value. In other words, this provides a default value to use as a replacement if the keyword's current value is invalid. If None, there is no replacement value and the keyword is unfixable.

option : str

Output verification option. Must be one of "fix", "silentfix", "ignore", "warn", or "exception". May also be any combination of "fix" or "silentfix" with "+ignore", +warn, or +exception" (e.g. ``"fix+warn"). See astropy:verify for more info.

errlist : list

A list of validation errors already found in the FITS file; this is used primarily for the validation system to collect errors across multiple HDUs and multiple calls to req_cards.