Returns <tt>true</tt> if this list contains the specified element.
More formally, returns <tt>true</tt> if and only if this list contains
at least one element <tt>e</tt> such that
<tt>(o==null ? e==null : o.equals(e))</tt>.
@param o element whose presence in this list is to be tested
@return <tt>true</tt> if this list contains the specified element
Returns <tt>true</tt> if this list contains the specified element. More formally, returns <tt>true</tt> if and only if this list contains at least one element <tt>e</tt> such that <tt>(o==null ? e==null : o.equals(e))</tt>.
@param o element whose presence in this list is to be tested @return <tt>true</tt> if this list contains the specified element