'Load parameters from a file.
Such a file can be generated using the C{openssl} command line tool as
following:
C{openssl dhparam -out dh_param_1024.pem -2 1024}
Please refer to U{OpenSSL\'s C{dhparam} documentation
<http://www.openssl.org/docs/apps/dhparam.html>} for further details.
@param filePath: A file containing parameters for Diffie-Hellman key
exchange.
@type filePath: L{FilePath <twisted.python.filepath.FilePath>}
@return: An instance that loads its parameters from C{filePath}.
@rtype: L{DiffieHellmanParameters
<twisted.internet.ssl.DiffieHellmanParameters>}'

@classmethod
def fromFile(cls, filePath):

    return cls(filePath)
