diff --git a/fastkml/geometry.py b/fastkml/geometry.py
index 936e8f8d..53fd1b10 100644
--- a/fastkml/geometry.py
+++ b/fastkml/geometry.py
@@ -132,10 +132,12 @@ def __init__(
     def _set_altitude_mode(self, element):
         if self.altitude_mode:
             # XXX add 'relativeToSeaFloor', 'clampToSeaFloor',
-            assert(self.altitude_mode in [
-                'clampToGround',
-                'relativeToGround', 'absolute'
-            ])
+            if self.altitude_mode not in ['clampToGround', 'relativeToGround',
+                                          'absolute']:
+                raise AssertionError("Altitude mode not in "
+                                     " not in clampToGround,"
+                                     "'relativeToGround' or"
+                                     "'absolute' mode")
             if self.altitude_mode != 'clampToGround':
                 am_element = etree.SubElement(
                     element, "%saltitudeMode" % self.ns
diff --git a/fastkml/kml.py b/fastkml/kml.py
index 22321e82..5fe02033 100644
--- a/fastkml/kml.py
+++ b/fastkml/kml.py
@@ -408,7 +408,9 @@ def snippet(self):
             if isinstance(self._snippet, dict):
                 text = self._snippet.get('text')
                 if text:
-                    assert (isinstance(text, basestring))
+                    if not (isinstance(text, basestring)):
+                        raise TypeError("text should be of"
+                                             "type basestring")
                     max_lines = self._snippet.get('maxLines', None)
                     if max_lines is None:
                         return {'text': text}
@@ -490,7 +492,9 @@ def etree_element(self):
             if isinstance(self.snippet, basestring):
                 snippet.text = self.snippet
             else:
-                assert (isinstance(self.snippet['text'], basestring))
+                if not (isinstance(self.snippet['text'], basestring)):
+                    raise TypeError("text snippet should be of"
+                                             "type basestring")
                 snippet.text = self.snippet['text']
                 if self.snippet.get('maxLines'):
                     snippet.set('maxLines', str(self.snippet['maxLines']))
@@ -641,7 +645,9 @@ def append(self, kmlobj):
                 "Features must be instances of "
                 "(Folder, Placemark, Document)"
             )
-        assert(kmlobj != self)
+        if not (kmlobj != self):
+            raise AssertionError(" kml object should not be instance of class"
+                                 "(self)")
 
 
 class _Overlay(_Feature):
@@ -656,7 +662,7 @@ class _Overlay(_Feature):
 
     _color = None
     # Color values expressed in hexadecimal notation, including opacity (alpha)
-    # values. The order of expression is alpOverlayha, blue, green, red
+    # values. The order of expression is alphaOverlay, blue, green, red
     # (AABBGGRR). The range of values for any one color is 0 to 255 (00 to ff).
     # For opacity, 00 is fully transparent and ff is fully opaque.
 
@@ -1098,7 +1104,7 @@ def from_element(self, element):
 
         logger.warn('No geometries found')
         logger.debug(u'Problem with element: {}'.format(etree.tostring(element)))
-        #raise ValueError('No geometries found')
+        # raise ValueError('No geometries found')
 
     def etree_element(self):
         element = super(Placemark, self).etree_element()