'Convert headers to botocore keyword agruments.'

def _headers_to_botocore_kwargs(self, headers):

    mapping = CaselessDict({'Content-Type': 'ContentType', 'Cache-Control': 'CacheControl', 'Content-Disposition': 'ContentDisposition', 'Content-Encoding': 'ContentEncoding', 'Content-Language': 'ContentLanguage', 'Content-Length': 'ContentLength', 'Content-MD5': 'ContentMD5', 'Expires': 'Expires', 'X-Amz-Grant-Full-Control': 'GrantFullControl', 'X-Amz-Grant-Read': 'GrantRead', 'X-Amz-Grant-Read-ACP': 'GrantReadACP', 'X-Amz-Grant-Write-ACP': 'GrantWriteACP'})
    extra = {}
    for (key, value) in six.iteritems(headers):
        try:
            kwarg = mapping[key]
        except KeyError:
            raise TypeError(('Header    "%s"    is    not    supported    by    botocore' % key))
        else:
            extra[kwarg] = value
    return extra
