17659: add deprecated is_series()

src/sage/symbolic/all.py

@@ -4,6 +4,7 @@
 from constants import (pi, e, NaN, golden_ratio, log2, euler_gamma, catalan,
                        khinchin, twinprime, mertens, glaisher)
 from expression import Expression, solve_diophantine
+from series import SymbolicSeries
 from callable import CallableSymbolicExpressionRing
 
 from sage.symbolic.relation import solve, solve_mod, solve_ineq

src/sage/symbolic/expression.pyx

@@ -1996,6 +1996,19 @@ cdef class Expression(CommutativeRingElement):
         """
         return is_a_numeric(self._gobj)
 
+    def is_series(self):
+        """
+        TESTS::
+
+            sage: x.is_series()
+            doctest:...: DeprecationWarning: ex.is_series() is deprecated. Use isinstance(ex, SymbolicSeries) instead
+            See http://trac.sagemath.org/17659 for details.
+            False
+        """
+        from sage.misc.superseded import deprecation
+        deprecation(17659, "ex.is_series() is deprecated. Use isinstance(ex, SymbolicSeries) instead")
+        return False
+
     def is_terminating_series(self):
         """
         Return True if ``self`` is a series without order term.

src/sage/symbolic/series.pyx

@@ -82,6 +82,20 @@ cdef class SymbolicSeries(Expression):
         Expression.__init__(self, SR, 0)
         self._parent = SR
 
+    def is_series(self):
+        """
+        TESTS::
+
+            sage: ex = sin(x).series(x,5)
+            sage: ex.is_series()
+            doctest:...: DeprecationWarning: ex.is_series() is deprecated. Use isinstance(ex, SymbolicSeries) instead
+            See http://trac.sagemath.org/17659 for details.
+            True
+        """
+        from sage.misc.superseded import deprecation
+        deprecation(17659, "ex.is_series() is deprecated. Use isinstance(ex, SymbolicSeries) instead")
+        return True
+
     def is_terminating_series(self):
         """
         Return True if the series is without order term.