<element name=“card” xmlns=“relaxng.org/ns/structure/1.0”>
<attribute name="name"/> <attribute name="email"/> <attribute name="preferredFormat"> <choice> <value>html</value> <value>text</value> </choice> </attribute>
</element>
<element name=“card” xmlns=“relaxng.org/ns/structure/1.0”>
<attribute name="name"/> <attribute name="email"/> <attribute name="preferredFormat"> <choice> <value>html</value> <value>text</value> </choice> </attribute>
</element>