<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def generate_authorization_header(access_key, date, region, signed_headers, signature):
 """ Generate authorization header. :param access_key: Server access key. :param date: Date is input from :meth:`datetime.datetime` :param region: Region should be set to bucket region. :param signed_headers: Signed headers. :param signature: Calculated signature. """

    signed_headers_string = ';'.join(signed_headers)
    credential = generate_credential_string(access_key, date, region)
    auth_header = [_SIGN_V4_ALGORITHM, 'Credential=' + credential + ',',
                   'SignedHeaders=' + signed_headers_string + ',',
                   'Signature=' + signature]
    return ' '.join(auth_header)