fix jagged arrays of covariance keys
fix jagged arrays of covariance keys

partial derivative
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* only use x + [dx, -dx] if x is ndarray and dtype is not 'object'
* otherwise use the zip method which works fine anyway (just switch all to
 this?
* put try-except around using all keys, because they might be jagged, if
 so, make a list
* make sure pre-grouped x is really ndarray
* if x is ndarray and its dtype is object, it's jagged so make it a list
* before scaling covarinace, equalize rows of jagged array by repeating
 singletons
* unset logging level of LOGGER, so it inherits from root

Signed-off-by: Mark Mikofski <318ee9014fd8bbcb598d57c182125ac60961dfd8@sunpowercorp.com>

SunPower/UncertaintyWrapper