generate_key!

        # OpenSSL::PKey::DH.generate_key!

(from ruby core)
### Implementation from DH
---
    dh.generate_key! -> self

---

Generates a private and public key unless a private key already exists.
If this DH instance was generated from public DH parameters (e.g. by
encoding the result of DH#public_key), then this method needs to be
called first in order to generate the per-session keys before performing
the actual key exchange.

**Deprecated in version 3.0**. This method is incompatible with OpenSSL
3.0.0 or later.

See also OpenSSL::PKey.generate_key.

Example:
    # DEPRECATED USAGE: This will not work on OpenSSL 3.0 or later
    dh0 = OpenSSL::PKey::DH.new(2048)
    dh = dh0.public_key # #public_key only copies the DH parameters (contrary to the name)
    dh.generate_key!
    puts dh.private? # => true
    puts dh0.pub_key == dh.pub_key #=> false

    # With OpenSSL::PKey.generate_key
    dh0 = OpenSSL::PKey::DH.new(2048)
    dh = OpenSSL::PKey.generate_key(dh0)
    puts dh0.pub_key == dh.pub_key #=> false