diff --git a/pyext/src/mmcif.py b/pyext/src/mmcif.py
index 3fe48767..3f73edf9 100644
--- a/pyext/src/mmcif.py
+++ b/pyext/src/mmcif.py
@@ -252,7 +252,7 @@ def __init__(self, state, component, start, end, count, hier, asym_unit):
 
     def combine(self, other):
         # todo: don't combine if one fragment is rigid and the other flexible
-        if (type(other) == type(self) and
+        if (type(other) == type(self) and     # noqa: E721
                 other.asym_unit.seq_id_range[0]
                 == self.asym_unit.seq_id_range[1] + 1):
             self.asym_unit.seq_id_range = (self.asym_unit.seq_id_range[0],
diff --git a/pyext/src/plotting/topology.py b/pyext/src/plotting/topology.py
index 1a73374b..f3697509 100644
--- a/pyext/src/plotting/topology.py
+++ b/pyext/src/plotting/topology.py
@@ -73,9 +73,9 @@ def add_rmf(self, rmf_fn, nframe):
 
         for component_name in self.selections:
             for seg in self.selections[component_name]:
-                if type(seg) == str:
+                if isinstance(seg, str):
                     s = IMP.atom.Selection(hier, molecule=seg)
-                elif type(seg) == tuple:
+                elif isinstance(seg, tuple):
                     s = IMP.atom.Selection(
                         hier, molecule=seg[2],
                         residue_indexes=range(seg[0], seg[1] + 1))
diff --git a/pyext/src/restraints/saxs.py b/pyext/src/restraints/saxs.py
index 54bce717..0c2c35f9 100644
--- a/pyext/src/restraints/saxs.py
+++ b/pyext/src/restraints/saxs.py
@@ -64,7 +64,7 @@ def __init__(self, input_objects, saxs_datafile, weight=1.0,
                 maxq = 0.4
             else:
                 maxq = 0.5
-        elif type(maxq) == float:
+        elif isinstance(maxq, float):
             if maxq < 0.01 or maxq > 4.0:
                 raise Exception(
                     "SAXSRestraint: maxq must be set between 0.01 and 4.0")
diff --git a/pyext/src/topology/__init__.py b/pyext/src/topology/__init__.py
index 27ab5ec5..e1856f09 100644
--- a/pyext/src/topology/__init__.py
+++ b/pyext/src/topology/__init__.py
@@ -765,7 +765,7 @@ def add_representation(self,
         # unify formatting for extra breaks
         breaks = []
         for b in bead_extra_breaks:
-            if type(b) == str:
+            if isinstance(b, str):
                 breaks.append(int(b)-1)
             else:
                 breaks.append(b)
@@ -1223,7 +1223,8 @@ def __key(self):
                 self.pdb_index, self.internal_index)
 
     def __eq__(self, other):
-        return type(other) == type(self) and self.__key() == other.__key()
+        return (type(other) == type(self)    # noqa: E721
+                and self.__key() == other.__key())
 
     def __hash__(self):
         return hash(self.__key())