Undefined names

[cclauss]

flake8 testing of https://github.com/dfd-tud/deda on Python 3.6.3

$ flake8 . --count --select=E901,E999,F821,F822,F823 --show-source --statistics

./libdeda/extract_yd.py:192:25: F821 undefined name 'A'
            plt.scatter(A[:,1], A[:,0]*-1);
                        ^
./libdeda/extract_yd.py:192:33: F821 undefined name 'A'
            plt.scatter(A[:,1], A[:,0]*-1);
                                ^
./libdeda/extract_yd.py:193:25: F821 undefined name 'A'
            plt.scatter(A[mask2][:,1], A[mask2][:,0]*-1,color="r");
                        ^
./libdeda/extract_yd.py:193:40: F821 undefined name 'A'
            plt.scatter(A[mask2][:,1], A[mask2][:,0]*-1,color="r");
                                       ^
./libdeda/extract_yd.py:194:25: F821 undefined name 'B'
            plt.scatter(B[mask2][:,1], B[mask2][:,0]*-1,color="g");
                        ^
./libdeda/extract_yd.py:194:40: F821 undefined name 'B'
            plt.scatter(B[mask2][:,1], B[mask2][:,0]*-1,color="g");
                                       ^
./libdeda/pattern_handler.py:434:24: F821 undefined name 'parser'
        return getattr(parser,name)(self.m)
                       ^
7     F821 undefined name 'A'
7