[#bsl-unordered_multiset-06c-contains-0c]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_multiset-06c.adoc[unordered_multiset]::contains
:relfileprefix: ../../
:mrdocs:

Return `true` if this unordered multiset contains an element whose key is equivalent to the specified `key`.

== Synopsis

Declared in `<bslstl_unorderedmultiset.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class LOOKUP_KEY>
bool
contains(LOOKUP_KEY const& key) const
requires BloombergLP::bslmf::IsTransparentPredicate<HASH, LOOKUP_KEY>::value &&
            BloombergLP::bslmf::IsTransparentPredicate<EQUAL,
                                                       LOOKUP_KEY>::value;
----


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