Merge pull request scikit-learn#5579 from rvraghav93/inspect_fix

[MRG+1] FIX inspect.argspect is deprecated; use signature

Author: GaelVaroquaux

sklearn/gaussian_process/kernels.py

@@ -31,7 +31,7 @@
 from ..metrics.pairwise import pairwise_kernels
 from ..externals import six
 from ..base import clone
-
+from sklearn.externals.funcsigs import signature
 
 class Hyperparameter(namedtuple('Hyperparameter',
                                 ('name', 'value_type', 'bounds',
@@ -116,15 +116,21 @@ def get_params(self, deep=True):
         # to represent
         cls = self.__class__
         init = getattr(cls.__init__, 'deprecated_original', cls.__init__)
-        args, varargs, kw, default = inspect.getargspec(init)
-        if varargs is not None:
+        init_sign = signature(init)
+        args, varargs = [], []
+        for parameter in init_sign.parameters.values():
+            if (parameter.kind != parameter.VAR_KEYWORD and
+                    parameter.name != 'self'):
+                args.append(parameter.name)
+            if parameter.kind == parameter.VAR_POSITIONAL:
+                varargs.append(parameter.name)
+
+        if len(varargs) != 0:
             raise RuntimeError("scikit-learn kernels should always "
                                "specify their parameters in the signature"
                                " of their __init__ (no varargs)."
                                " %s doesn't follow this convention."
                                % (cls, ))
-        # Remove 'self' and store remaining arguments in params
-        args = args[1:]
         for arg in args:
             params[arg] = getattr(self, arg, None)
         return params

sklearn/gaussian_process/tests/test_kernels.py

@@ -4,7 +4,7 @@
 # Licence: BSD 3 clause
 
 from collections import Hashable
-import inspect
+from sklearn.externals.funcsigs import signature
 
 import numpy as np
 
@@ -81,8 +81,8 @@ def test_kernel_theta():
         _, K_gradient = kernel(X, eval_gradient=True)
 
         # Determine kernel parameters that contribute to theta
-        args, varargs, kw, default = \
-            inspect.getargspec(kernel.__class__.__init__)
+        init_sign = signature(kernel.__class__.__init__).parameters.values()
+        args = [p.name for p in init_sign if p.name != 'self']
         theta_vars = map(lambda s: s.rstrip("_bounds"),
                          filter(lambda s: s.endswith("_bounds"), args))
         assert_equal(