Remove unnecessary util.callable usage

Fixes: #4850

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### Description
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Removes usage of `util.callable`.

### Checklist
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This pull request is:

- [ ] A documentation / typographical error fix
	- Good to go, no issue or tests are needed
- [x] A short code fix
	- please include the issue number, and create an issue if none exists, which
	  must include a complete example of the issue.  one line code fixes without an
	  issue and demonstration will not be accepted.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.   one line code fixes without tests will not be accepted.
- [ ] A new feature implementation
	- please include the issue number, and create an issue if none exists, which must
	  include a complete example of how the feature would look.
	- Please include: `Fixes: #<issue number>` in the commit message
	- please include tests.

**Have a nice day!**

Closes: #4851
Pull-request: https://github.com/sqlalchemy/sqlalchemy/pull/4851
Pull-request-sha: a0ccdff2cb74f5e944d8baccc269c382b591c8e2

Change-Id: I79918f44becbc5dbefdc7ff65128695c1cabed1d

3 files changed, 5 insertions, 5 deletions

diff --git a/lib/sqlalchemy/sql/ddl.py b/lib/sqlalchemy/sql/ddl.py
index ef6614b61..48d4bc9dc 100644
--- a/lib/sqlalchemy/sql/ddl.py
+++ b/lib/sqlalchemy/sql/ddl.py
@@ -258,7 +258,7 @@ class DDLElement(roles.DDLRole, Executable, _DDLCompiles):
     def _check_ddl_on(self, on):
         if on is not None and (
             not isinstance(on, util.string_types + (tuple, list, set))
-            and not util.callable(on)
+            and not callable(on)
         ):
             raise exc.ArgumentError(
                 "Expected the name of a database dialect, a tuple "
diff --git a/lib/sqlalchemy/sql/schema.py b/lib/sqlalchemy/sql/schema.py
index f0a697728..d5ee1057b 100644
--- a/lib/sqlalchemy/sql/schema.py
+++ b/lib/sqlalchemy/sql/schema.py
@@ -2222,13 +2222,13 @@ class ColumnDefault(DefaultGenerator):
             raise exc.ArgumentError(
                 "ColumnDefault may not be a server-side default type."
             )
-        if util.callable(arg):
+        if callable(arg):
             arg = self._maybe_wrap_callable(arg)
         self.arg = arg
 
     @util.memoized_property
     def is_callable(self):
-        return util.callable(self.arg)
+        return callable(self.arg)
 
     @util.memoized_property
     def is_clause_element(self):
@@ -4211,7 +4211,7 @@ class MetaData(SchemaItem):
                     for name, schname in zip(available, available_w_schema)
                     if extend_existing or schname not in current
                 ]
-            elif util.callable(only):
+            elif callable(only):
                 load = [
                     name
                     for name, schname in zip(available, available_w_schema)
diff --git a/lib/sqlalchemy/sql/type_api.py b/lib/sqlalchemy/sql/type_api.py
index 11407ad2e..9c5f5dd47 100644
--- a/lib/sqlalchemy/sql/type_api.py
+++ b/lib/sqlalchemy/sql/type_api.py
@@ -1461,7 +1461,7 @@ def to_instance(typeobj, *arg, **kw):
     if typeobj is None:
         return NULLTYPE
 
-    if util.callable(typeobj):
+    if callable(typeobj):
         return typeobj(*arg, **kw)
     else:
         return typeobj