Replaces everything in code_array from pys_file

def to_code_array(self):
        """Replaces everything in code_array from pys_file"""

        state = None

        # Check if version section starts with first line
        first_line = True

        # Reset pys_file to start to enable multiple calls of this method
        self.pys_file.seek(0)

        for line in self.pys_file:
            if first_line:
                # If Version section does not start with first line then
                # the file is invalid.
                if line == "[Pyspread save file version]\n":
                    first_line = False
                else:
                    raise ValueError(_("File format unsupported."))

            if line in self._section2reader:
                state = line

            elif state is not None:
                self._section2reader[state](line)