A Copyright object contains a Header paragraph and a list of additional
    Files or License paragraphs.  It provides methods to iterate over those
    paragraphs, in addition to adding new ones.  It also provides a mechanism
    for finding the Files paragraph (if any) that matches a particular
    filename.

    Typical usage::

        with io.open('debian/copyright', 'rt', encoding='utf-8') as f:
            c = copyright.Copyright(f)

            header = c.header
            # Header exposes standard fields, e.g.
            print('Upstream name: ', header.upstream_name)
            lic = header.license
            if lic:
                print('Overall license: ', lic.synopsis)
            # You can also retrive and set custom fields.
            header['My-Special-Field'] = 'Very special'

            # Find the license for a given file.
            paragraph = c.find_files_paragraph('debian/rules')
            if paragraph:
                print('License for debian/rules: ', paragraph.license)

            # Dump the result, including changes, to another file.
            with io.open('debian/copyright.new', 'wt', encoding='utf-8') as f:
                c.dump(f=f)

    It is possible to build up a Copyright from scratch, by modifying the
    header and using add_files_paragraph and add_license_paragraph.  See the
    associated method docstrings.
    Nú