diff --git a/README.md b/README.md
index 44e07c2..02fef04 100644
--- a/README.md
+++ b/README.md
@@ -21,43 +21,75 @@ Copy the `micromail.py` file to your device. You will need to install the `datet
 
 ### Class MicromailClient
 
-`class micromail.MicromailClient(host: str, port: int, ssl: bool=False, starttls: bool=False)`
-: Create a new SMTP client.
+- `class micromail.MicromailClient(host: str, port: int = 0, ssl: bool = False, starttls: bool = False)`
 
-`MicromailClient.connect()`
-: Establish a connection to the SMTP server. The connection is kept alive until `MicromailClient.quit()` is called.
+    Create a new SMTP client.
 
-`MicromailClient.login(username: str, password: str)`
-: Login to the SMTP server with the provided username and password. `PLAIN` and `LOGIN` authentication methods are currently supported.
+- `MicromailClient.connect()`
 
-`MicromailClient.write(data: bytearray)`
-: Write `data` of type `bytearray` on the server.
 
-`MicromailClient.send_command(*cmd: bytearray) -> code: bytearray, response: list[bytearray]`
-: Send command to the SMTP server; returns status code and response.
+    Establish a connection to the SMTP server. The connection is kept alive until `MicromailClient.quit()` is called.
 
-`MicromailClient.ehlo() -> res: list[bytearray]`
-: Send SMTP EHLO command to the server and return response.
+- `MicromailClient.login(username: str, password: str)`
 
-`MicromailClient.starttls()`
-: Send SMTP STARTTLS command and enable SSL on socket.
+    Login to the SMTP server with the provided username and password. `PLAIN` and `LOGIN` authentication methods are currently supported.
 
-`MicromailClient.new_message(to: str|list[str], sender: None|str=None)`
-: Create a new email; sender defaults to username.
+- `MicromailClient.write(data: str | bytes)`
 
-`MicromailClient.headers(headers:dict={})`
-: Define email headers; supported headers are `date` (`str|datetime`, defaults to `datetime.now()`), `from` (`str`, defaults to `new_message` `sender`), `to` (`str|list[str]`, defaults to `new_message` `to`), `subject` (`str`).
+    Write `data` of type `bytearray` on the server.
 
-`MicromailClient.write_line(content:str|bytearray)`
-: Write message line; `\r\n` is appended to `content`.
+- `MicromailClient.send_command(*cmd: str | bytes, code: int | list[int] = []) -> tuple[int, list[str]]`
 
-`MicromailClient.send()`
-: Send current email.
+    Send command to the SMTP server; returns status code and list of response lines.
 
-`MicromailClient.quit()`
-: Quit the SMTP server and disconnect from socket.
+- `MicromailClient.read_res(cmd: str = "", code: int | list[int] = []) -> tuple[int, list[str]]`
+
+    Read response from the SMTP server; returns status code and list of response lines.
+
+- `MicromailClient.ehlo() -> list[str]`
+
+    Send SMTP EHLO command to the server and return response.
+
+- `MicromailClient.starttls()`
+
+    Send SMTP STARTTLS command and enable SSL on socket.
+
+- `MicromailClient.new_message(to: str | list[str], sender: str | None = None)`
+
+    Create a new email; sender defaults to username.
+
+- `MicromailClient.headers(headers: dict[str, str])`
+
+    Define email headers; supported headers are `date` (`str`, defaults to current date), `from` (defaults to `new_message` `sender`), `to` (defaults to `new_message` `to`), `subject` (`str`).
+
+- `MicromailClient.write_line(content: str)`
+
+    Write message line; `\r\n` is appended to `content`.
+
+- `MicromailClient.send()`
+
+    Send current email.
+
+- `MicromailClient.quit()`
+
+    Quit the SMTP server and disconnect from socket.
 
 ### Functions
 
-`format_date(date: datetime)`
-: Return date formatted as email date string.
+- `format_date(date: datetime) -> str`
+
+    Return date formatted as email date string.
+
+### Exceptions
+
+- `Error`
+
+    Standard module error.
+
+- `NoSocketError`
+
+    Raised when an operation on the socket is asked but the client is not connected to any socket.
+
+- `SMTPError(cmd: str, code: int, message: str)`
+
+    Raised when an unexpected SMTP response code is received.
diff --git a/micromail.py b/micromail.py
index 0a4d507..966d0f6 100644
--- a/micromail.py
+++ b/micromail.py
@@ -110,7 +110,7 @@ class MicromailClient:
 
     def write(self, data: str | bytes) -> None:
         if self.socket is None:
-            raise Error("No socket to write to.")
+            raise NoSocketError
 
         if isinstance(data, str):
             data = data.encode()