function validateExplicitKey(component, parentType) {
  if (component._store.validated || component.key != null) {
    return;
  }
  component._store.validated = true;

  warnAndMonitorForKeyUse(
    'react_key_warning',
    'Each child in an array should have a unique "key" prop.',
    component,
    parentType
  );
}
Ensure that every component either is passed in a static location, in an
array with an explicit keys property defined, or in an object literal
with valid key property.

@internal
@param {*} component Statically passed child of any type.
@param {*} parentType component's parent's type.
@return {boolean}