null CAMPANHA DO DIA C

Um erro ocorreu enquanto processava o modelo. 
The following has evaluated to null or missing:
==> photo  [in template "20102#20128#null" at line 3, column 104]

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Tip: If the failing expression is known to be legally refer to something that's sometimes null or missing, either specify a default value like myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing</#if>. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)??
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FTL stack trace ("~" means nesting-related):
	- Failed at: #if photo.getSiblings()?has_content  [in template "20102#20128#null" at line 3, column 99]
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1<dl><dt>Capa do artigo:</dt><dd><#if image.getData()?? && image.getData() != ""> 
2	<img alt="${image.getAttribute("alt")}" data-fileentryid="${image.getAttribute("fileEntryId")}" src="${image.getData()}" /> 
3</#if></dd><dt>Conteúdo:</dt><dd>${content.getData()}</dd><dt>Foto da galeria (opcional):</dt><dd><#if photo.getSiblings()?has_content> 
4	<#list photo.getSiblings() as cur_photo> 
5		<a href="${cur_photo.getData()}"> 
6			${languageUtil.format(locale, "download-x", "Foto da galeria (opcional)", false)} 
7		</a> 
8	</#list> 
9</#if></dd><dt>Título da foto (ocional):</dt><dd>${photo.photo_title.getData()}</dd><dt>Subtítulo (opcional):</dt><dd>${photo.photo_description.getData()}</dd></dl>