# sympy__sympy-18532
# Loki Mode Multi-Agent Patch
# Attempts: 1

This repository doesn't contain the SymPy codebase. The issue is about the SymPy project (sympy/sympy). Based on the architect's analysis and my knowledge of SymPy's codebase, I'll generate the patch for the `atoms()` method in `sympy/core/basic.py` and the corresponding test file.

```
--- a/sympy/core/basic.py
+++ b/sympy/core/basic.py
@@ -435,8 +435,8 @@ class Basic(with_metaclass(ManagedProperties)):
         &, currentmodule:: sympy
 
         Examples
         ========
 
         >>> from sympy import I, pi, sin
         >>> from sympy.abc import x, y
         >>> (1 + x + 2*sin(y + I*pi)).atoms()
-        {1, 2, I, pi, x, y}
+        {1, 2, I, pi, x, y}
 
         If one or more types are given, the results will contain only
         those types of atoms.
@@ -498,7 +498,7 @@ class Basic(with_metaclass(ManagedProperties)):
         if types:
             types = tuple(
                 [t if isinstance(t, type) else type(t) for t in types])
         else:
-            types = (Atom,)
+            types = None
         result = set()
         for expr in preorder_traversal(self):
-            if isinstance(expr, types):
+            if types is None and not expr.args or types and isinstance(expr, types):
                 result.add(expr)
         return result
```

Let me provide the complete corrected patch:

--- a/sympy/core/basic.py
+++ b/sympy/core/basic.py
@@ -417,10 +417,10 @@ class Basic(with_metaclass(ManagedProperties)):
     def atoms(self, *types):
         """Returns the atoms that form the current object.
 
-        By default, only objects that are truly atomic and can't
-        be divided into smaller pieces are returned: symbols, numbers,
-        and number symbols like I and pi. It is possible to request
-        atoms of any type, however, as demonstrated below.
+        By default, only objects that have no ``.args`` (leaves of the
+        expression tree) are returned. It is possible to request
+        atoms of any type by passing specific types as arguments,
+        as demonstrated below.
 
         Examples
         ========
@@ -495,11 +495,11 @@ class Basic(with_metaclass(ManagedProperties)):
         """
         if types:
             types = tuple(
                 [t if isinstance(t, type) else type(t) for t in types])
-        else:
-            types = (Atom,)
         result = set()
         for expr in preorder_traversal(self):
-            if isinstance(expr, types):
+            if types and isinstance(expr, types):
+                result.add(expr)
+            elif not types and not expr.args:
                 result.add(expr)
         return result
 
--- a/sympy/core/tests/test_basic.py
+++ b/sympy/core/tests/test_basic.py
@@ -70,7 +70,7 @@ def test_atoms():
     assert b21.atoms() == set()
 
 def test_free_symbols_empty():
-    assert b21.atoms() == set()
+    assert Basic().atoms() == {Basic()}
 
 
 def test_doit():