public function isIndexedProvider()
{
return ['key value pairs' => [['key' => 'value'], false], 'empty array' => [[], true], 'list' => [['foo', 'bar'], true], 'zero-indexed numeric int keys' => [[0 => 'foo', 1 => 'bar'], true], 'zero-indexed numeric string keys' => [['0' => 'foo', '1' => 'bar'], true], 'non-zero-indexed keys' => [[1 => 'foo', 2 => 'bar'], false], 'non-sequential keys' => [[0 => 'foo', 2 => 'bar'], false]];
}