for operands of the key type; thus the key type must not be a function, map, or
slice.
If the key type is an interface type, these
comparison operators must be defined for the dynamic key values;
failure will cause a <a href="#Run_time_panics">run-time panic</a>.
</p>

<pre>
map[string]int
map[*T]struct{ x, y float64 }
map[string]interface{}
</pre>

<p>