Final pep8 changes to edge.py

import math

import warnings

from collections import MutableMapping

        """

        matches = self.matches

        for column, default in {'x_offset': 0, 'y_offset': 0, 'correlation': 0, 'reference': -1}.items():

            if not column in self.matches.columns:

            if column not in self.matches.columns:

                self.matches[column] = default

        # Build up a composite mask from all of the user specified masks