imgtool: Fix PEP8 warnings on modules in this PR

from .general import KeyClass

class ECDSAUsageError(Exception):

    pass

class ECDSA256P1Public(KeyClass):

    def __init__(self, key):

        self.key = key

        return priv

    def export_private(self, path, passwd=None):

        """Write the private key to the given file, protecting it with the optional password."""

        """Write the private key to the given file, protecting it with '

          'the optional password."""

        if passwd is None:

            enc = serialization.NoEncryption()

        else:

}

valid_formats = ['openssl', 'pkcs8']

def load_signature(sigfile):

    with open(sigfile, 'rb') as f:

        signature = base64.b64decode(f.read())

        return signature

def save_signature(sigfile, sig):

    with open(sigfile, 'wb') as f:

        signature = base64.b64encode(sig)

        f.write(signature)

def load_key(keyfile):

    # TODO: better handling of invalid pass-phrase

    key = keys.load(keyfile)

@click.command(help='Dump public key from keypair')

def getpub(key, encoding, lang):

    if encoding and lang:

        raise click.UsageError('Please use only one of `--encoding/-e` or `--lang/-l`')

        raise click.UsageError('Please use only one of `--encoding/-e` '

                               'or `--lang/-l`')

    elif not encoding and not lang:

        # Preserve old behavior defaulting to `c`. If `lang` is removed,

        # `default=valid_encodings[0]` should be added to `-e` param.

              help='Path to the file to which signature will be written. '

              'The image signature will be encoded as base64 formatted string')

@click.option('--vector-to-sign', type=click.Choice(['payload', 'digest']),

              help='send to OUTFILE the payload or payload''s digest instead of '

              'complied image. These data can be used for external image '

              help='send to OUTFILE the payload or payload''s digest instead '

              'of complied image. These data can be used for external image '

              'signing')

@click.command(help='''Create a signed or unsigned image\n

               INFILE and OUTFILE are parsed as Intel HEX if the params have

        }

    img.create(key, public_key_format, enckey, dependencies, boot_record,

               custom_tlvs, int(encrypt_keylen), clear, baked_signature, pub_key,

               vector_to_sign)

               custom_tlvs, int(encrypt_keylen), clear, baked_signature,

               pub_key, vector_to_sign)

    img.save(outfile, hex_addr)

    if sig_out is not None: