<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def proper_case_section(self, section):
 """Verify proper casing is retrieved, when available, for each dependency in the section. """

        # Casing for section.
        changed_values = False
        unknown_names = [k for k in section.keys() if k not in set(self.proper_names)]
        # Replace each package with proper casing.
        for dep in unknown_names:
            try:
                # Get new casing for package name.
                new_casing = proper_case(dep)
            except IOError:
                # Unable to normalize package name.
                continue

            if new_casing != dep:
                changed_values = True
                self.register_proper_name(new_casing)
                # Replace old value with new value.
                old_value = section[dep]
                section[new_casing] = old_value
                del section[dep]
        # Return whether or not values have been changed.
        return changed_values