code: def proper_case_section(self, 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
docs: Verify proper casing is retrieved, when available, for each
          dependency in the section.