fix for flake8

Author: vivekvedant

lib/matplotlib/axes/_axes.py

@@ -5748,9 +5748,9 @@ def _pcolorargs(self, funcname, *args, shading='auto', **kwargs):
 
         if shading == 'flat':
             if (Nx, Ny) != (ncols + 1, nrows + 1):
-                raise TypeError('Dimensions of C %s are incompatible with'
-                                ' X (%d) and/or Y (%d); X and y should be one larger than  C see help(%s)' % (
-                                    C.shape, Nx, Ny, funcname))
+                raise TypeError(f"Dimensions of X({Nx}) and y({Ny}) should"
+                                f"be one larger than C{C.shape}"
+                                f"see help({funcname})")
         else:    # ['nearest', 'gouraud']:
             if (Nx, Ny) != (ncols, nrows):
                 raise TypeError('Dimensions of C %s are incompatible with'

lib/matplotlib/tests/test_axes.py

@@ -1438,11 +1438,12 @@ def test_pcolorflaterror():
     with pytest.raises(TypeError, match='Dimensions of C'):
         ax.pcolormesh(x, y, Z, shading='flat')
 
+
 def test_samesizepcolorflaterror():
     fig, ax = plt.subplots()
     x, y = np.meshgrid(np.arange(5), np.arange(3))
     Z = x + y
-    with pytest.raises(TypeError, match=r".*X and y should be one larger than  C"):
+    with pytest.raises(TypeError, match=r".*one larger than C"):
         ax.pcolormesh(x, y, Z, shading='flat')