Change double quotes to single quotes

Author: mgeier

setup.py

@@ -72,10 +72,10 @@ def get_tag(self):
     package_data=package_data,
     zip_safe=zip_safe,
     python_requires='>=2.6',
-    setup_requires=["CFFI>=1.0"],
+    setup_requires=['CFFI>=1.0'],
     install_requires=['CFFI>=1.0'],
     extras_require={'NumPy': ['NumPy']},
-    cffi_modules=["sounddevice_build.py:ffibuilder"],
+    cffi_modules=['sounddevice_build.py:ffibuilder'],
     author='Matthias Geier',
     author_email='Matthias.Geier@gmail.com',
     description='Play and Record Sound with Python',

sounddevice.py

@@ -2060,7 +2060,7 @@ class PortAudioError(Exception):
     def __str__(self):
         errormsg = self.args[0] if self.args else ''
         if len(self.args) > 1:
-            errormsg = "{0} [PaErrorCode {1}]".format(errormsg, self.args[1])
+            errormsg = '{0} [PaErrorCode {1}]'.format(errormsg, self.args[1])
         if len(self.args) > 2:
             host_api, hosterror_code, hosterror_text = self.args[2]
             hostname = query_hostapis(host_api)['name']
@@ -2556,7 +2556,7 @@ def _check(err, msg=''):
 
     errormsg = _ffi.string(_lib.Pa_GetErrorText(err)).decode()
     if msg:
-        errormsg = "{0}: {1}".format(msg, errormsg)
+        errormsg = '{0}: {1}'.format(msg, errormsg)
 
     if err == _lib.paUnanticipatedHostError:
         # (gh82) We grab the host error info here rather than inside

sounddevice_build.py

@@ -1,7 +1,7 @@
 from cffi import FFI
 
 ffibuilder = FFI()
-ffibuilder.set_source("_sounddevice", None)
+ffibuilder.set_source('_sounddevice', None)
 ffibuilder.cdef("""
 int Pa_GetVersion( void );
 const char* Pa_GetVersionText( void );
@@ -317,5 +317,5 @@
     FILE* __stderrp;  /* macOS */
 """)
 
-if __name__ == "__main__":
+if __name__ == '__main__':
     ffibuilder.compile(verbose=True)