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