>>> df = spark.range(10)
>>> df.sample(0.0000000001, 3).show()
+---+
| id|
+---+
+---+

>>> df = spark.range(10)
>>> df.sample(True, 0.1, 1).show()
+---+
| id|
+---+
|  0|
|  4|
+---+
>>> df.sample(True, 0.5, 1).show()
+---+
| id|
+---+
|  0|
|  0|
|  3|
|  4|
|  8|
+---+
