+ Adds a field declaration *field_type* named *field_name* to
+ this event class.
+
+ *field_type* must be one of:
+
+ * :class:`IntegerFieldDeclaration`
+ * :class:`FloatingPointFieldDeclaration`
+ * :class:`EnumerationFieldDeclaration`
+ * :class:`StringFieldDeclaration`
+ * :class:`ArrayFieldDeclaration`
+ * :class:`SequenceFieldDeclaration`
+ * :class:`StructureFieldDeclaration`
+ * :class:`VariantFieldDeclaration`
+
+ :exc:`ValueError` is raised on error.