fix _check_values_dtype_in_probs method in Distribution class (#27046)

python/paddle/distribution.py

@@ -138,7 +138,7 @@ class Distribution(object):
         convert value's dtype to be consistent with param's dtype.
 
         Args:
-            param (int|float|list|numpy.ndarray|Tensor): low and high in Uniform class, loc and scale in Normal class.
+            param (Tensor): low and high in Uniform class, loc and scale in Normal class.
             value (Tensor): The input tensor.
 
         Returns:
@@ -152,6 +152,7 @@ class Distribution(object):
                 )
                 return core.ops.cast(value, 'in_dtype', value.dtype,
                                      'out_dtype', param.dtype)
+            return value
 
         check_variable_and_dtype(value, 'value', ['float32', 'float64'],
                                  'log_prob')