diff --git a/var/spack/repos/builtin/packages/doxygen/package.py b/var/spack/repos/builtin/packages/doxygen/package.py
index d6b72af2f9cf5f2628e82175f0b96facb77c7948..b2e9582b5a9ad7a823592ebaf2e56be5f53f4554 100644
--- a/var/spack/repos/builtin/packages/doxygen/package.py
+++ b/var/spack/repos/builtin/packages/doxygen/package.py
@@ -23,7 +23,6 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 from spack import *
-import sys
 
 
 class Doxygen(Package):
@@ -40,13 +39,13 @@ class Doxygen(Package):
     version('1.8.10', '79767ccd986f12a0f949015efb5f058f')
 
     # graphviz appears to be a run-time optional dependency
-    variant('graphviz', default=True, description='Build with dot command support from Graphviz.')
+    variant('graphviz', default=True, description='Build with dot command support from Graphviz.')  # NOQA: ignore=E501
 
     depends_on("cmake@2.8.12:")
     depends_on("flex")
     depends_on("bison")
 
-    #optional dependencies
+    # optional dependencies
     depends_on("graphviz", when="+graphviz")
 
     def install(self, spec, prefix):
diff --git a/var/spack/repos/builtin/packages/ghostscript/package.py b/var/spack/repos/builtin/packages/ghostscript/package.py
index 3a121111a3cad30242765fe8ea8923b5da4e7545..707f65c90284b531785a8b6cb350f9b2f13ed6dc 100644
--- a/var/spack/repos/builtin/packages/ghostscript/package.py
+++ b/var/spack/repos/builtin/packages/ghostscript/package.py
@@ -24,6 +24,7 @@
 ##############################################################################
 from spack import *
 
+
 class Ghostscript(Package):
     """an interpreter for the PostScript language and for PDF. """
     homepage = "http://ghostscript.com/"
@@ -34,7 +35,7 @@ class Ghostscript(Package):
     parallel = False
 
     def install(self, spec, prefix):
-        configure("--prefix=%s" %prefix, "--enable-shared")
+        configure("--prefix=%s" % prefix, "--enable-shared")
 
         make()
         make("install")
diff --git a/var/spack/repos/builtin/packages/graphviz/package.py b/var/spack/repos/builtin/packages/graphviz/package.py
index a527d7ae5085ffbcbb49fff7f7bbb86c78aa2a4b..2f99015ba2618d44cc6554a214502cf4eefd2efe 100644
--- a/var/spack/repos/builtin/packages/graphviz/package.py
+++ b/var/spack/repos/builtin/packages/graphviz/package.py
@@ -25,6 +25,7 @@
 from spack import *
 import sys
 
+
 class Graphviz(Package):
     """Graph Visualization Software"""
     homepage = "http://www.graphviz.org"
@@ -36,7 +37,7 @@ class Graphviz(Package):
     # related to missing Perl packages. If spack begins support for Perl in the
     # future, this package can be updated to depend_on('perl') and the
     # ncecessary devel packages.
-    variant('perl', default=False, description='Enable if you need the optional Perl language bindings.')
+    variant('perl', default=False, description='Enable if you need the optional Perl language bindings.')  # NOQA: ignore=E501
 
     parallel = False
 
@@ -47,7 +48,7 @@ class Graphviz(Package):
 
     def install(self, spec, prefix):
         options = ['--prefix=%s' % prefix]
-        if not '+perl' in spec:
+        if '+perl' not in spec:
             options.append('--disable-perl')
 
         # On OSX fix the compiler error: