[SPARK-13047][PYSPARK][ML] Pyspark Params.hasParam should not throw an error

Pyspark Params class has a method `hasParam(paramName)` which returns `True` if the class has a parameter by that name, but throws an `AttributeError` otherwise. There is not currently a way of getting a Boolean to indicate if a class has a parameter. With Spark 2.0 we could modify the existing behavior of `hasParam` or add an additional method with this functionality.

In Python:
```python
from pyspark.ml.classification import NaiveBayes
nb = NaiveBayes()
print nb.hasParam("smoothing")
print nb.hasParam("notAParam")
```
produces:
> True
> AttributeError: 'NaiveBayes' object has no attribute 'notAParam'

However, in Scala:
```scala
import org.apache.spark.ml.classification.NaiveBayes
val nb  = new NaiveBayes()
nb.hasParam("smoothing")
nb.hasParam("notAParam")
```
produces:
> true
> false

cc holdenk

Author: sethah <seth.hendrickson16@gmail.com>

Closes #10962 from sethah/SPARK-13047.

1 files changed, 5 insertions, 2 deletions

diff --git a/python/pyspark/ml/param/__init__.py b/python/pyspark/ml/param/__init__.py
index ea86d6aeb8..bbf83f0310 100644
--- a/python/pyspark/ml/param/__init__.py
+++ b/python/pyspark/ml/param/__init__.py
@@ -179,8 +179,11 @@ class Params(Identifiable):
         Tests whether this instance contains a param with a given
         (string) name.
         """
-        param = self._resolveParam(paramName)
-        return param in self.params
+        if isinstance(paramName, str):
+            p = getattr(self, paramName, None)
+            return isinstance(p, Param)
+        else:
+            raise TypeError("hasParam(): paramName must be a string")
 
     @since("1.4.0")
     def getOrDefault(self, param):