darkfi-sdk-python: Clean up doc and support zkbin.k()

src/sdk/python/Makefile

@@ -5,6 +5,9 @@ MATURIN = maturin
 
 all:
 	$(MATURIN) build --release
-	@echo "You can install this wheel with pip install"
+	@echo "You can install this wheel with make install"
+dev:
+	$(MATURIN) develop --release
+
 
 .PHONY: all

src/sdk/python/README.md

@@ -4,7 +4,7 @@ Python bindings for some parts of the `darkfi-sdk` and the `zkvm`.
 
 ## Build and install
 
-1. Install `maturin` via your package manager or from whatever source.
+1. Install `maturin` via your package manager or from source.
 2. Run `make` to build the wheel
 3. (Optional) Run pip install --user <path_to_wheel>
 
@@ -15,16 +15,14 @@ For a development version you can use a venv:
 ```
 $ python3 -m venv venv
 $ source venv/bin/activate
-(venv) $ maturin develop --release
+(venv) $ make dev
 ```
 
 ## Usage
 
 ```
-$ python3
+$ python
 >>> import darkfi_sdk_py
->>> darkfi_sdk_py.__dir__()
->>>
 >>> from darkfi_sdk_py.base import Base
 >>> a = Base.from_u64(42)
 >>> b = Base.from_u64(69)

src/sdk/python/src/zk_binary.rs

@@ -64,6 +64,10 @@ impl ZkBinary {
             })
             .collect()
     }
+
+    fn k(&self) -> u32 {
+	self.0.k
+    }
 }
 
 pub fn create_module(py: pyo3::Python<'_>) -> pyo3::PyResult<&PyModule> {